LONDON (Reuters) - Hormones in semen may help to ease female depression because women whose partners don't use condoms are less likely to feel down.
Scientists at the State University of New York suspect the mood-altering hormones are absorbed through the vagina and make women feel good but they stressed that their results are not an excuse for unprotected sex.
"I want to make it clear that we are not advocating that people abstain from using condoms," Gordon Gallup, who led the study, told New Scientist magazine on Wednesday.
"Clearly an unwanted pregnancy or a sexually transmitted disease would more than offset any advantageous psychological effects of semen," he added.
The researchers assessed the moods of 300 female students using a standard questionnaire. A score of more than 17 was considered moderately depressed.
Women whose partners never used condoms scored about eight on the test while those who never had sex without condoms scored 11.3. Women who weren't having sex at all scored about 13.5.
Depression in the students who sometimes or never used condoms was more severe the longer they went without sex.
The scientists said they looked at other factors, such as the use of oral contraceptives, frequency of sex and personality type, but found that none could account for the findings.
The magazine said the results are not a complete surprise because scientists know that semen contains several mood-altering hormones including testosterone.
"Some of these have been detected in a woman's blood within hours of exposure to semen," the magazine said.
The scientists suspect semen will have the same effect on women regardless of how they are exposed to it.