A pair of 3-year-old identical twin girls were abducted by Hamas in their surprise attack on Israel on October 7, 2023. One of them was abducted separately from her parents and twin. The twins’ mother repeatedly asked her captors to reunite her with her daughter. Only 10 days later, when the mother was moved with one of the twins to be imprisoned in a hospital room, were the twins reunited after the mother recognized her other daughter’s voice when she heard her cry (Weiss, 2023). Another pair of identical twins, 26-year-old brothers abducted to Gaza that same day, are still being held in separation according to testimonies of hostages that have already been released (Bunkall, 2024). Although it is impossible to know for sure that the twin separation is intentional, we assert that the damages of twin separation are a small but significant example of the cruelty to children by Hamas, the organization that brought devastation to an entire region, and call for prioritizing the reunification of children with their families (Knafo-Noam & Segal, 2024).

Children’s Wartime Trauma

The effects of war trauma on anyone are devastating but can be especially detrimental and long-lasting on children (Chemtob et al., 2007; Joshi & O’Donnell, 2003) A recent example, concerning children in Ukraine who are suffering from the horrific images they have seen and from the loss of their loved ones, highlights some of the unique vulnerabilities of children living through a war, especially as they manifest over time (Chubko & Parafeniuk, 2024). As another example, there is evidence that refugee children from Syrian and other conflict zones encounter high levels of risk and stress that affects family functioning, mental health, and cognitive development (Hazer & Gredebäck, 2023). Children may lack the coping skills of adults and be unable to verbalize the traumatic experiences they have suffered and still suffer (Fivush, 1998; Terr, 1988). Studies indicate that exposure to war and terrorism is strongly associated with mental, behavioral, and emotional difficulties in children, including elevated rates of anxiety, depression, and post-traumatic stress disorder (Malchiodi & Crenshaw, 2017; Pine et al., 2005). Thus, it is particularly important to raise awareness about the impact of war on children in general, while also highlighting the experiences of specific children whose circumstances may increase their vulnerability.

The war initiated by Hamas resulted in widespread suffering and numerous casualties, significantly impacting children. Hamas’s attack led to Israeli retaliation, and this war is estimated to have resulted in the deaths of thousands of children in Gaza (Boukari et al., 2024). The number of childhood casualties has also been significantly exacerbated by Hamas, launching rockets from civilian areas such as schools and hospitals, as well as preventing civilians from fleeing under attack (Fox, 2024). In addition, due to rocket attacks from Gaza and Lebanon and the Israeli offensive, tens of thousands of children in Gaza, Lebanon, and Israel were displaced (Agence France Presse, 2023; Tétrault-Farber, 2023). Lastly, children’s indirect exposure to the atrocities of war further contributes to their trauma. Jerusalem (Israel’s capital and largest city) has been relatively safe from the face-to-face acts of violence that happened on October 7th and had a relatively low number of alarms since the beginning of the war (13 in the first 2 months, compared to 42 in Tel Aviv, Israel’s second largest city and 197 in Ashqelon, the largest town close to Gaza; Home Front Command, 2024). Jerusalem children may have still been highly impacted by the war, partly due to media exposure, with over 30% exhibiting anxiety symptom severity that surpassed the clinical cutoff, indicating potentially clinically significant problems (Katsoty et al., 2024).

Hamas terrorists took the lives of dozens of children in towns, villages, and Kibbutzim, often in the presence of their parents. Reports have also emerged of children being burned and beheaded (Codish et al., 2024; Nelker-Zitser & Cohen, 2023). Additionally, Hamas abducted dozens of adolescents and children, for future use as leverage in negotiations. The children (except for two young brothers, including a 9-month-old hostage) were released during a temporary truce deal (November 22–December 1, 2023).

In a unique study, Katz and her colleagues (2024) analyzed the themes raised by children and adolescents who were freed in the hostage deal. Using 57 publicly available videotaped interviews, the authors found strong evidence for the impact of the abduction and captivity on the children. Specifically, children who were held captive by Hamas suffered severe physical, emotional, and psychological harm through multiple forms of abuse and trauma. Their experiences included the violent abduction itself, with some paraded publicly in Gaza as objects, subjected to beatings, spitting, and groping by mobs. While abducted, and subsequently, children witnessed extreme violence, including the murder of community members, family, and friends, and saw corpses and wounded people. During captivity, the children endured severe conditions, such as malnutrition, dehydration, medical neglect, lack of sanitation, and confinement in dark rooms. The captors used threats, emotional manipulation, and lies to undermine the children’s sense of belonging and hope. They were forced to stay silent, threatened with death if they spoke, and repeatedly told that Israel had abandoned them. Finally, children were repeatedly subject to emotional and physical abuse, including being victims or witnesses of sexual abuse.

Like other traumatic events, being kidnapped has detrimental consequences for the victims, including cognitive effects (e.g., impaired concentration), emotional effects (numbness and anxiety), and effects on social functioning (irritability and withdrawal) (Alexander & Klein, 2009; Navia & Ossa, 2003). Over the long term, effects can include learned helplessness, feelings of emptiness, PTSD, and other aspects of psychopathology (Alexander & Klein, 2009; Favaro et al., 2000; Wright et al., 2017). Children may be especially susceptible to the effects of abduction. Schoolchildren abducted in 1976 in Chowchilla, California, had long-term trauma even though they managed to escape the next day (Terr, 1983). For children held hostage for weeks by Hamas, the resulting impact is expected to be significantly more severe.

One important aspect of the captivity experience that children described was being separated from their family. Some children were abducted apart from their families or were abducted after family members were murdered. However, even if children were abducted with family members, some of them were kept separated from other hostages who were also members of their family, spending prolonged periods of isolation from their loved ones. Indeed, one of the children noted, “The hardest thing was to be without my parents, without anyone, just alone. It was insanely hard” (Katz et al., 2024, p. 8).

Twin Children: Unique Situations of Wartime Trauma and Loss

Psychological researchers have studied twins with increased frequency for assessing genetic and environmental influences on a wide range of human behaviors. They include, but are not limited to, general intelligence, personality, interests, and attitudes. The classic twin method is simple and elegant. The similarity of pairs of (virtually) genetically identical twins (monozygotic) is compared with that of non-identical or fraternal twins (dizygotic), who share half the genetic variance, on average. Greater resemblance between identical twins than fraternal twins is consistent with genetic influence on the trait in question. Most measured traits have been shown to be genetically influenced, at least in part (Knopik et al., 2017; N. L. Segal, 2000). However, twins, especially twin children, pose unique psychological situations and concerns regarding wartime trauma and loss.

Research is concerned with differences in the social relatedness of the two types of twins (twin relationship features, e.g., H. Segal et al., 2024) and what might happen were that bond to be disrupted (N. L. Segal et al., 2022). In such research, the focus is on the pair as the unit of interest. In particular, as developmental scientists studying twins, the viciousness toward the abducted twin children of whom we are aware attracted our immediate attention. The story of these twins deserves our focused attention, not only because of the likely impact of the abduction on the abducted children, but because it tells us about the detrimental effects of the forced separation of children from their loved ones. We note that the imposed severance of the twin bond in these circumstances is not more “significant” than the same act imposed upon other siblings. Instead, bringing attention to the twin bond and the abducted 3-year-old twins offers a unique example of the effects of wartime trauma and separation on the members of an especially vulnerable population.

Our research, along with that of our colleagues, demonstrates that the bond between identical twins represents one of the closest human social relationships (H. Segal & Knafo-Noam, 2021; N. L. Segal et al., 2022; Tancredy & Fraley, 2006). This exceptional connection is characterized by unparalleled levels of trust, acceptance, and enduring love. This finding has been reported by numerous studies, regardless of the age and ethnicity of the twins, and the theoretical approach and methods of the investigators (Neyer, 2002; N. L Segal, & H. Segal, in press; N. L. Segal et al., 2003). One of us has extensively studied the social relations between twins who were adopted separately as babies and reunited as adults, with the Minnesota Study of Twins Reared Apart (N. L. Segal, 2012). The emotional reactions of the twins to their separation, after they were reunited, often included sadness, bitterness, and anger, as well as regret at the extended loss of the other twin. It was striking that closeness and familiarity were rated higher for the newly found twin than for the adopted sibling with whom the twin had been raised since childhood (N. L. Segal, 2012; N. L. Segal et al., 2003). These same emotions were expressed by newborn twins intentionally adopted apart, in the 1960s, by Louise Wise Services and secretly studied until they turned 12. Additional details of the tragic stories of their separate adoptions and scientific exploitation have been documented (N. L. Segal, 2021).

Even infant twins as young as 3 or 4 months of age acknowledge the occasional absence of the small person in the adjacent crib—hearing their absent co-twin vocalize in the next room may cause their co-twin to stop moving or feeding, whereas twins sleeping together experience more quiet sleep and less distress than those sleeping apart (Brazleton, 1980; Hayward et al., 2015). Given the foregoing, what if one of the 3-year-old twins held hostage by Hamas had not been found, had not been released, or—very worst-case scenario—fallen sick or been murdered by her captors? The responses of even very young twins to the loss of their twin sibling, due to accident or illness, can lead to an array of severe and long-lasting behavioral disturbances and disruptions.

Importantly, the loss of a twin during infancy or early childhood should not be underestimated, as it cannot simply be assumed that the surviving child is unaware of or unaffected by the loss. Interviews with parents indicate that surviving twins often display behaviors such as crying, seeking physical comfort, or sleeplessness (N. L. Segal, 2017). Even twins who never had the chance to know their co-twin due to prenatal or early loss still grieve the absence of this unique relationship. There is an impressive body of evidence showing that individuals who lose a twin prior to birth or shortly thereafter suffer from the loss of a potentially meaningful relationship (Woodward, 2010). In fact, the unique features of twin loss have been presented to juries in lawsuits involving both twin children and adults (N. L. Segal, 2000). Indeed, in a TV interview, the mother of the abducted twins described how their emotional behavior has changed, including the appearance of frequent tantrums despite their previously joyful temperament (Kushmaro, 2024). Although the tantrums likely reflect the effect of the abduction itself and other aspects of exposure to war, they could also be a consequence of the twins’ separation (Fraley & Tancredy, 2012).

Studies also reveal that for a twin, the death of their twin sibling at age fifteen or older—regardless of whether it occurs from natural causes, an accident, or other circumstances—is one of the most devastating losses, often exceeding the impact of losing a parent or a non-twin sibling (N. L. Segal et al., 2022). This finding was revealed through a survey asking twins to indicate their grief intensity for the loss of the twin and for any other relative who passed away during their lifetime, using a 1 (no grief) to 7 (total devastation, suicide point) scale. For both identical and fraternal twins, the loss of the twin received significantly higher ratings than those of other relatives. (One exception was a small sample of twins who had lost spouses, whose average rating for the deceased spouses matched that for the deceased cotwins.) More research is needed on twin loss, given how important and special this relationship is.

It is also important to consider the parents’ perspective on the loss of a twin child. Some people, including health professionals, have incorrectly assumed that the loss of a twin newborn is less devastating than the loss of a non-twin child, because one child remains (N. L. Segal, 1993). However, research has shown that parents of multiple birth babies and singleton babies mourn their loss to similar degrees (Richards et al., 2015; Wilson et al., 1982). One twin child is not a replacement for the other twin child. Another assumption is that young children may forget the loss with time. On the contrary, childhood experiences at age 3 years (the age the twins were abducted and placed apart) and beyond can be remembered (Drummey & Newcombe, 1995; Reardon, 2024). In fact, some studies found that a younger sibling’s birth can be recalled by adults when they were as young as 2 years, 4 months at the time (Nelson & Fivush, 2004).

It is also significant that the proliferation of twin images in movies and the media means that twin survivors of all ages will be confronted continually with painful reminders. Special support groups, such as Twinless Twins Support Group International (https://twinlesstwins.org/), have been established by twins to address the needs of all forms of twin loss. A similar group was established by the twin survivors of 9/11 (N. L. Segal, 2006). Twins who lost cotwins in the 9/11 attack on the World Trade Center in New York City also struggle with grief, as do their surviving children. Surviving twins are a constant reminder of the tragically murdered co-twin (N. L. Segal, 2006).

Separation from Family Members

The abducted twins and their mother remain separated from their father, who is still held captive in Gaza. As these words are being written (December 2024), close to 100 additional children in Israel are still forcibly separated from at least one of their parents held captive in Gaza. Separation of children from their parents has negative effects on their psychological functioning and mental health, exacerbated by the prolonged separation and additional adversities encountered by the child (Waddoups et al., 2019).

The Society for Research in Child Development has argued convincingly against separating young children from their parents in the past (Bouza et al., 2018). The abduction of children for political conflict purposes takes place in many war-torn zones around the world, from Nigeria to Ukraine (Secretary-General of the UN, 2023; Gossman et. al., 2024). Holding civilians as hostages is a severe violation of the laws of armed conflict and considered a war crime, while deliberate and widespread attacks on children are seen as a crime against humanity in international law (Van Beuren, 2021).

However, many professional organizations dedicated to children’s welfare have remained silent about the harm caused to children by Hamas actions and their consequences. In doing so, they risk normalizing actions directly aimed at hurting children in the context of combat or conflict (Fellig, 2024; Katz et al., 2024).

While we have emphasized the role of twin connectedness as a vulnerability in the case of twin loss, twin bonds can also be seen as a coping resource (Hegedűs et al., 2014). A pair of 10-month-old twins residing in one of the attacked Kibbutzim were hidden by their parents just before the parents were brutally murdered by Hamas terrorists. Fourteen hours passed until Israeli soldiers discovered the twins, who seemed to be in good physical condition. These twins will be brought up by their grandmother (Steinbuch, 2023). Another tragedy that affected twins concerns the story of 23-year-old identical Palestinian male twins mourning the loss of their entire family (NBC, 2023). Both of these stories are heartbreaking and tragic. The only consolation is that these twins will be together as they grow up and can offer emotional sustenance and support to one another (Tornero et al., 2018).

Acknowledging and condemning the crimes of Hamas and their devastating impact on thousands of children, while highlighting the essential role of family bonds in building resilience and providing emotional support for both twin and non-twin children affected by conflict, is not merely a moral obligation—it is a vital step toward safeguarding the well-being and future of innocent children in both Israel and Palestine. Working for freeing the hostages and reuniting children with their parents and other family members is a moral imperative for professional organizations and the civilized world.

In conclusion, this commentary documents the severe psychological and emotional trauma resulting from young children’s exposure to the horrors of war, particularly the separation from a loved one. Further research is needed on twin separation during crises and its long-term psychological impact. Such research should follow twins and other children affected by war to examine their psychological sequelae, emotional support systems, and coping mechanisms, as well as to deepen our understanding of the broader effects of war on twins and family separations. As highlighted, the focus on twins underscores the profound consequences of enforced separation from an individual with whom one shares the closest of human social relationships. Special attention must be given to the unique vulnerabilities of twins and children separated from their families, considering the critical importance of the twin bond and the child-parent bond.