Evolutionary theory incorporates both evolution and sociology to understand sexual behavior. In order to understand sexual behavior in humans, evolutionary theorists study animal sexual patterns and look for evolutionary trends. They believe that sexuality ex-
ists for the purpose of reproducing the species, and individual sexuality is designed to maximize the chances of passing on one’s genes. According to evolutionary theorists, the winners in the game of life are those who are most successful at transmitting their genes to the next generation.
Think about the qualities you look for in a partner. Students often tell me that they are looking for someone who is physically attractive, monogamous, has a sense of humor, and is intelligent, honest, extroverted, fun, and sensitive. An evolutionary theorist would argue that these qualities have evolved to ensure that a person would be able to provide healthy offspring and care for them well. A physically attractive person is more likely to be physically fit and healthy. Could this be important to us because of their reproductive capabilities? Evolutionary theorists would say so. They would also argue that qualities such as monogamy, honesty, and sensitivity would help ensure that a partner will be reliable and help raise the offspring.
Some sexual activities have evolved to ensure the survival of the species. Evolutionary theorists believe that premarital sex is resisted because pregnancy in a single woman would be much less desirable for the species (because there would be only one parent for the offspring). They also believe that orgasms have evolved to make sexual intercourse pleasurable; this, in turn, increases the frequency that people engage in it and therefore the possibility of reproduction is increased. In Chapter 1 we discussed how the evolution of an upright posture changed the way the human species engaged in sexual intercourse.
Differences between the sexes in sexual desire and behavior are also thought to have evolved. The double standard, which states that men are free to have casual sex whereas women are not, exists because men produce millions of sperm per day and women produce only one viable ovum per month. Males try to “spread their seed” in order to ensure the reproduction of their family line, whereas females need to protect the one ovum they produce each month. When women become pregnant, they have a 9-month biological commitment ahead of them (and some would argue a lifelong commitment as well).
Evolutionary theory has received a considerable amount of criticism, however, particularly because evolutionary theorists tend to ignore the influence of both prior learning and societal influences on sexuality.