Mystery of the female orgasm’s origin SOLVED: Scientists claim the ‘big O’ evolved in humans to help prehistoric women ovulate during sex to aid conception
- Scientists say there is no biological reason for a female orgasm
- Its evolutionary origins and purpose has been the topic of much speculation
- Researchers believe it is a remnant of a long-defunct biological process
- Comes from a process found in some mammals where copulation triggers ovulation
Why women orgasm has long baffled science with no good biological reason for the cascade of pleasure felt by a woman as she reaches climax.
But researchers now believe it may have evolved in early humans to induce ovulation during sexual intercourse.
Orgasms were once vitally important to trigger ovulation – when the female releases an egg – during the sexual act.
In many animals, such as rabbits, ferrets, cats and camels this is still the case, as ovulation happens during sex.
Experts have been grappling to try and find an evolutionary reason for the cascade of pleasure felt by a woman as she reaches climax. Researchers now believe that it first evolved in early humans to induce ovulation (stock)
But this does not happen in humans or great apes. They instead ovulate once in a regular cycle, ranging from around every 28 days in humans, every 29 days in Orangutans and up to every 37 days in chimps.
But scientists suggest that at one time, during an earlier stage of evolution, ovulation in humans was triggered by a female orgasm during sex.
The authors from Yale University said: ‘The existence of female orgasm is intriguing for two reasons: On the one hand, female orgasm is not necessary for female reproductive success, and on the other hand, this neuro-endocrine reflex is too complex to be an evolutionary accident’.
‘Neuroendocrine’ refers to a combination of the stimulation of nerves and the production of hormones.
Researchers from Yale University set about to test the theory that orgasms are an evolutionary throwback to when humans were at an earlier stage of evolution.
The authors treated female rabbits – which ovulate during sex – with fluoxetine, a drug known to inhibit orgasm.
Researchers found that after treatment with fluoxetine, rabbits were 30 per cent less likely to ovulate than untreated rabbits.
While the exact mechanism of how orgasm triggers ovulation in rabbits is unknown, the authors suggest that as stopping orgasm reduces ovulation, it must have a role in triggering the release of eggs.
In conclusion the authors write that orgasm induce ovulation is ‘a mechanism that still exists in many animals but lost its role in others.
The orgasm releases a vast amount of endorphins and chemicals into the body, as well as feelings of arousal and pleasure, and it may be a remnant of this ancient process to aid in conception (stock)
‘Here we provide experimental evidence, strengthening the likelihood that female orgasm evolved from copulation induced ovulation.
‘This finding helps interpreting otherwise difficult to explain aspects of female sexuality, such as the low rate of female orgasm during intercourse.’
While the function of the orgasm has changed in humans, previous research has suggested that evolutionary changes has also made it harder for women to achieve orgasm.
The clitoris, which for most women needs stimulation for them to achieve orgasm, has moved over time to a less central position, so it no longer receives direct stimulation during penetration.