Semen acts as an
Exclusive from New Scientist
makes you happy. That's the remarkable conclusion of a study
comparing women whose partners wear condoms with those whose
The study, which is bound to provoke controversy, showed that
the women who were directly exposed to semen were less depressed.
The researchers think this is because mood-altering hormones in
semen are absorbed through the vagina. They say they have ruled
out other explanations.
"I want to make it clear that we are not advocating that
people abstain from using condoms," says Gordon Gallup, the
psychologist at the State University of New York who led the team.
"Clearly an unwanted pregnancy or a sexually transmitted
disease would more than offset any advantageous psychological
effects of semen."
His team divided 293 female students into groups depending on
how often their partners wore condoms, and assessed their
happiness using the Beck Depression Inventory, a standard
questionnaire for assessing mood. People who score over 17 are
considered moderately depressed.
The team found that women whose partners never used condoms
scored 8 on average, those who sometimes used them scored 10.5,
those who usually used them scored 15 and those who always used
them scored 11.3. Women who weren't having sex at all scored 13.5.
What's more, the longer the interval since they last had sex,
the more depressed the women who never or sometimes used condoms
got. But the time since the last sexual encounter made no
difference to the mood of women who usually or always used
The team also found that depressive symptoms and suicide
attempts were more common among women who used condoms regularly
compared with those who didn't. The results will appear in the
journal Archives of Sexual Behavior.
And Gallup told New Scientist that his team already has
unpublished data from a larger group of 700 women confirming these
findings. In this study, the always-use-condoms group were more
depressed than the usually-use-condoms group, suggesting the
discrepancy in the smaller study was a sampling error, he says.
But is it really the semen that affects women's mood? The
researchers say they looked at alternative explanations such as
whether women who seldom use condoms took oral contraceptives, how
often they had sex, the strength of relationships, and the
possibility that having a certain type of personality influenced
the decision to use condoms. But none of these factors can explain
their findings, they say.
In fact, the results aren't a complete surprise because semen
does contain several mood-altering hormones, including
testosterone, oestrogen, follicle-stimulating hormone, luteinising
hormone, prolactin and several different prostaglandins. Some of
these have been detected in a women's blood within hours of
exposure to semen.
The question many people will ask is whether oral sex could
have the same mood-enhancing effects. "Since the steroids in
birth control pills survive the digestion process, I would assume
that the same holds true for at least some of the chemicals in
semen," Gallup says.
"I understand that among some gay males who have anal
intercourse, it is not uncommon to attempt to retain the semen for
extended periods of time," he adds. "Suggesting, of
course, that there may be psychological effects." But further
research will be needed to confirm whether exposure to semen
through oral or anal sex really does affect mood in heterosexual
or homosexual partners.
But why should semen have such an effect? "It makes no
sense to me for this phenomenon to have evolved," says
Satoshi Kanazawa, an evolutionary psychologist at the Indiana
University of Pennsylvania. But Gallup counters that men whose
semen promotes long-term mood enhancement might have more chances
to indulge in sexual activity.