Minnesota study suggests we're doomed to regrettable sex from birth

Abstinence now, insanity later.

​Teenagers can be stupid. Which is why, conventional wisdom says, they ought to keep it in their pants until the hormonal seas have ebbed enough for sane and safe sexual decisions to be made. Right?

Well, according to a new study, our sexual IQ is probably set long before "the talk," and it seems we're doomed to lives of regrettable sex whether we like it or not.

"Nobody has actually tested whether early sexual initiation actually causes sexual risk-taking," says psychologist Marina Bornovalova, who started the study at the U of M. "There's an association--that doesn't mean one causes the other."

Bornovalova tackled the issue using data from the Minnesota Twin Family Study, a database of 1,000 pairs of identical and fraternal twins who've been tracked since the age of 11. She found 158 cases of identical twins who became sexually active at different ages, using age 16 as the cut-off for "early initiation." In each pair of twins she looked at, one had sex before the age of 16, and the other twin had sex later, sometimes well into adulthood.

Those 158 pairs were surveyed again at age 24 about the riskiness of their sex lives--how many non-serious partners they had ("One-night stands and booty calls," says Bornovalova), if they engaged in sexual behavior while drunk or on drugs, or if they'd had a pregnancy before the age of 20. The results?

"They do not differ on rates of pregnancy and sexual risk-taking," says Bornovalova. "It's a genetic or a familial effect rather than a casual effect."

If she's right, it means sex-ed or abstinence-only programs that hammer the message to JUST WAIT aren't necessarily rewriting teenagers' sexual futures, just pushing a big pause button.

"We really need to be looking at other things," says Bornovalova. "A genetic propensity for impulsive behavior or some familial variable or poverty."

The study, "Testing the Role of Adolescent Sexual Initiation in Later-Life Sexual Risk Behavior: A Longitudinal Twin Design," will be out in the next copy of Psychological Science.