A thing on a man can actually promote ovulation in a woman

A new study shows that semen, long thought to be a sperm carrier, contains a substance that triggers ovulation and other pregnancy hormonal responses in female mammals, a finding that could lead to new approaches to human fertility treatment.

Like most female mammals, human females are spontaneous ovulators, meaning they release eggs fairly regularly regardless of sexual activity. However, some animals, such as camels and rabbits, release fertile eggs only when they are sexually active, a process called inductive ovulation.

However, as early as 1985, some Chinese scientists challenged this traditional theory, suggesting that there might be an ovulation-inducing factor (OIF) in semen. According to Gregg Adams, a veterinarian and reproductive biologist at the University of Saskatchewan in Saskatoon, Canada, this hypothesis was completely contrary to mainstream theory and "was ignored by people, including myself."

But when Adams and his colleagues tested this hypothesis 10 years later, they were surprised by the results. In 2005, the team injected male ostrich semen into the hind legs of female ostriches, which are closely related to camels, to see if the ostriches would ovulate without genital stimulation. To their surprise, injecting semen into the female ostriches' bloodstream produced "very effective ovulation," Adams said.

That set off a seven-year search to see if OIF exists in semen. Now, in a study published on August 20 in the Proceedings of the National Academy of Sciences, Adams and colleagues say they collected semen from ostriches and bulls and tested it in both spontaneously and induced ovulatory animals, and that the results show that OIF is indeed present in the semen of these animals.