Swedish researchers said Tuesday what women have suspected all along: that marital woes can often be attributed to men's genetic make-up, linking a common male gene to relationship problems.

This gene affects the angiotensin receptor system that plays a critical role in social monogamy for male prairie voles.

Researchers found that disabling the FucM gene - which influences the levels of oestrogen to which the brain is exposed - caused the mice to behave as if they were male as they grew up.