I just finished reading a very interesting book by Jared Diamond, an evolutionary scholar, entitled “Why is Sex Fun?” In this book he attempts to determine why humans are virtually the only species of all animals that has sex for pleasure.  All other species except for bonobo chimps, engage in intercourse exclusively for procreation.  Other oddities about humans include the following: female humans are one of the rare species to have hidden ovulation, or in other words do not reveal themselves when they are ovulating, as opposed to most animals who are visibly “in heat”; female humans have menopause and engage in sexual intercourse even after menopause, another rare occurrence: and humans are one of the rare species which is decidedly monogamous in its sexual relations. So why on earth are humans so radically different from other animals in their sexuality?

Dr. Diamond makes the case that human sexuality evolved the way it did due to the reproductive systems of humans. Human babies are unique in the animal kingdom in that they are very large in relation to other animal babies and take years upon years to develop into full functioning individuals. For example, the average weight of a human baby is about 6 lbs, but the average weight of a gorilla baby is 3 lbs, even though adult gorillas are much larger than adult humans. Also most animal babies can forage and fend for themselves within months or even weeks after birth, while human babies take years upon years to be self-reliant. In addition, many animals lay multiple eggs or give birth to multiple “litters”, while human babies are usually born individually, unless there is an exception.

So what you have here is a situation where the human baby is more delicate and precious than other animal babies, simply because it is born alone and is very vulnerable for an extended duration. Thus, in order for the human baby to survive, it is imperative that it is raised by both parents, female and male. The male parent is necessary to provide extra protection and nourishment for the human baby, which the female parent alone would have trouble providing.  Other animals, due to being born in groups and maturing more rapidly, need less parental supervision in order for the species to survive, so it is much less necessary for both biological parents to stay together.

And this is really the underlying reason behind why humans behave sexually in the way they do and tend to pair-bond into monogamous relationships during a majority of their lifetime. It all comes down to evolution and the survival of the species.  Diamond argues that humans are evolutionarily hard-wired to act in such a way to best promote the continual advancement and survival of the species. As a result, a female human, unlike other animals, engages in sex continuously with her male partner, even when she is not ovulating in order to keep him attracted and bonded to her, so that he will stay with her if/when they have children. Further, female humans conceal their ovulation so that male humans do not know when the optimum time would be to inseminate her, so as a result, he will be more likely to stay with her and continually try to inseminate her rather than run off to engage with other females who may or may not be ovulating. The instinct to pair-bond and live monogamously with another partner is also part of the process of ensuring that both biological parents are available to human baby, so that it may survive.

So in the end, what is the answer to Diamond’s fundamental question- Why is sex fun? It is fun to ensure multiple sexual intercourse with the same partner, which leads to pair-bonding and emotional feelings such as love, which leads to monogamy, which in the end, ensures the survival of the human species. We as humans are pre-programmed to enjoy sex- it’s the only way we can survive.