It can be jarring to hear that your significant other looks like one of your parents, but don't be too quick to panic. Research reveals that heterosexual people often choose partners who resemble a parent of the opposite sex, but it doesn't mean that you're secretly lusting after mom or dad.

Men and women are often attracted to people who look like their parents.

A 2004 study published in the Royal Society journal of biological sciences looked into how parents shaped heterosexual women's coupling tendencies. The researchers looked at homogamy — the idea that we choose mates who are similar to ourselves. They hypothesized that physical resemblance between women and their husbands was due to imprinting, or using their fathers as templates for future partners, rather than simply being attracted to men who looked similar to themselves.

The study compared women's fathers' phenotypes, the biological term for a person's observable traits such as height and eye color, to those of their husbands. Its findings confirmed that women were likely to marry men who resembled their fathers, even if they were adopted.

Men also tended to pick female spouses whose faces slightly resembled their mothers, according to a 2001 study conducted by the Department of General Psychology at Hungary's University of Pécs.

Both the Royal Society and University of Pécs study linked imprinting to mating behavior and concluded that our experiences with our parents, rather than the genes we share with them, are why we often match up with daddy or mommy look-a-likes. These observations have been echoed in studies focused on individual traits such as eye and hair color and ethnicity.

A 1979 study conducted in Hawaii and published in the Journal of Social Psychology looked at 577 brides and 403 grooms who had married twice and were raised by mixed ethnic parents. The study's authors observed that people tended to couple up with spouses of the same ethnicity as their parent of the opposite sex. This was the case even in second marriages and after "prolonged interactions with persons of the opposite sex."

As of yet, no studies directly examine how family members shape who homosexual people choose as spouses.

Relax, it doesn't make you a perv.

As Tamsin Saxton, a Senior Lecturer in Psychology at Northumbria University, pointed out on IFL Science, imprinting doesn't mean that you've repressed fantasies about incest, even if you are drawn to men or women who possess similar physical traits to your relatives. In fact, people tend to be distinctly unattracted to their parents and siblings from a young age.

Says Saxton:

"If anything, we seem to find our immediate family members unattractive. For instance, people find the very idea of sexual relationships with their siblings deeply unappealing. This aversion seems to develop automatically through two distinct processes. One process turns off attraction to those that we spend a lot of time with during childhood. The other turns off attraction to any infants that our mother looks after a lot."

Too, Sigmund Freud's belief that all boys are sexually attracted to their mothers is relatively unpopular among today's psychologists (as are many of Freud's other ideas, like using cocaine to treat symptoms of depression).

Saxton also noted that we aren't the only species that exhibits these tendencies. Birds also seek out mates that resemble their 'rents, according to a 1998 study.

The quality of your relationship with your parents also shapes who you're attracted to.

Despite the trope that unresolved 'mommy or daddy issues' will land you a parent surrogate for a mate, the Royal Society and University of Pécs studies found that the opposite was the case. Those who had supportive parents were more likely to gravitate towards partners who looked like them than people who had distant or troubled relationships with their mothers and fathers.

Adopted women who had close relationships with their adoptive fathers were more likely to choose a mate who resembled them than women whose adoptive fathers were not emotionally supportive, according to the Royal Society study.

The University of Pécs study also observed that men who were "more frequently rejected by their mother during childhood" were less likely to chose female mates who looked like their moms that men with supportive mothers.

Next time someone points out that your S.O. looks a little familiar, no need to cringe. It probably just means you had a happy childhood. Why not give your folks a call and say thanks?

[h/t IFL Science]