Many factors related to human sexuality influence oxytocin release. Oxytocin, produced in different areas throughout the body, has hormonal and neurological effects. Its hormonal effects prompt breastfeeding, uterine contractions during labor and sexual arousal in both men and women. Within the brain, oxytocin release has a wider range of effects concerning pair bonding and sexual arousal. Research into oxytocin has shown promise in using it as a treatment for autism.
Despite having a greater effect on female sexuality, oxytocin is present in both men and women. In women, the ovaries release oxytocin during the beginning of each menstrual cycle. During labor, it prompts uterine contractions; the hormone later plays a large role in breastfeeding. In men, oxytocin release occurs in the testes during sexual arousal, though in much smaller amounts compared to women. As of 2011, the role of hormonal oxytocin in men is still somewhat unclear due to the majority of research focusing on the hormone's role in female reproduction.
Hormonal oxytocin has more subtle effects within the realm of sexual arousal. Its affects on human physiology reduce fear and increase trust. This change is necessary for orgasm to occur in both men and women.
Oxytocin produced in the ovaries and testes cannot reach the human brain due to the blood-brain barrier. The brain produces its own oxytocin to complement the biological effects the hormone has on human sexuality. In men and women, neural oxytocin release causes pair bonding in both sexual and non-sexual relationships. For example, having an individual pet a dog for a few minutes causes neural oxytocin release in both human and animal; this research partially explains the affinity humans have had for dogs for thousands of years.
The largest release of neural oxytocin in humans occurs immediately after a woman gives birth. The presence of oxytocin when a mother sees her child for the first time starts the mother's maternal instinct. Hormonal oxytocin released through breastfeeding reinforces these feelings over the following months. Research on animals has revealed that oxytocin does not maintain the maternal instinct past the first few months of the child's life; rather, it creates patterns of maternal behavior that eventually do not require oxytocin release to be maintained.
Research into oxytocin release has suggested that synthetic oxytocin may be able to treat autism. Two research trials in the 2000s treated autistic patients with oxytocin administered nasally. In most cases, patients briefly developed better communication skills and more appropriate social behaviors. Though oxytocin treatments may one day help individuals with autism, the negative side effects associated with continuous oxytocin release means there are still many hurdles to overcome before synthetic oxytocin becomes a long-term treatment option.