YOUR genes won鈥檛 lead you to the altar, but they might summon you to the
divorce courts. A new study of twins suggests that genetic make-up has a strong
influence on whether or not your marriage will last鈥攖hough not whether
you鈥檒l get married in the first place.
Beth Jerskey, Michael Lyons and their colleagues at Boston University in
Massachusetts compared marriage and divorce rates in identical and non-identical
male twins. They gleaned their data from a registry of male twins who served in
the US military during the Vietnam war. In interviews in 1987鈥攊ntended to
diagnose mental disorders鈥攕ome 8000 of these twins stated whether they had
ever married, whether they were still in their first marriage, and if not, how
their first marriage ended.
Sure enough, identical twins鈥攚ho share the same genes鈥攚ere more
likely to follow the same patterns of divorce than non-identical twins, who
share roughly half their genes like ordinary siblings. This suggests there鈥檚 a
significant genetic influence on divorce.
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But there was no difference between identical and non-identical twins when it
came to whether or not they got married in the first place, suggesting this is
entirely determined by your environment. 鈥淭hat surprises me,鈥� says Lyons. 鈥淪o
many traits鈥攅ven very complex social ones鈥攈ave a detectable genetic
颈苍蹿濒耻别苍肠别.鈥�
Lyons鈥檚 hunch is that environment swamps any genetic influence on marriage
because people are generally young when they tie the knot, and their decision
rests heavily on the success or failure of their parents鈥� marriage. But once
you鈥檙e in a marriage, other factors kick in.
He thinks the genetic influence on divorce is related to factors such as drug
abuse, depression and alcoholism, which have a genetic component. The team found
that twins who were pathological gamblers, for instance, were 2.8 times more
likely to get divorced than the norm for the day. 鈥淎lmost any kind of
psychopathology is going to make staying married harder,鈥� says Lyons.
He thinks this kind of study is important because it helps reveal the roots
of behaviour patterns. 鈥淚t鈥檚 not 鈥榟old the presses鈥�, let鈥檚 talk to marriage
councillors,鈥� says Lyons. 鈥淏ut I think this helps us to better understand human
苍补迟耻谤别.鈥�