In Scientific American, Holly Dunsworth wrote that homo sapiens is the only species that understands the birds and the bees. Even apes don’t comprehend the concept that sex leads to babies. Animals don’t need to understand it because they are motivated by instincts. All they need to know is that they like to have sex and the rest works out just fine for the preservation of the species. Humans behave differently from other animals as a consequence of understanding of the mechanisms of reproduction and this knowledge directly causes a lot of the qualities that separate humans from animals. For example, humans develop greater life-long connections with relatives like brothers and sisters, and human males make longstanding connections with their children and they even encourage their children to produce grandchildren. Most animals have no connection with family beyond a short period of parenting at most and some animals even eat their young when given the chance because they have little ability to recognize genetic familial relationships. Large, fundamental chunks of human culture directly stem from our knowledge of the birds and the bees: Patrilineal inheritance, hereditary monarchy, nepotism (in its original meaning), insults like “bastard,” trying to delay marriage/sex until reaching a degree of financial independence, infidelity norms, etc.
Primitive birth control methods would be feasible for apes. For example, apes could use the withdrawal method or ape females could hide during their estrous period. They could even attempt to end pregnancies that result from rape. But they have no reason to do these things without knowledge of the birds and the bees. In contrast, humans have always consciously tried to regulate fertility, but these efforts suddenly advanced in the past century because of new birth control technologies. That caused a sexual revolution by separating sex from reproduction.
For all of history until the 1800s, women had more than 5 births on average despite the fact that life expectancy was only about 35. Those were some busy mothers. They spent most of their sexually active lives either being pregnant or nursing babies. Today, the global average number of births per woman has fallen by more than half even though the average woman has more time for pregnancy because average female life expectancy has more than doubled and puberty is starting much younger.
Most of the drop in the global fertility occurred in just the past 50 years as sex has become increasingly divorced from reproduction. In the next 50 years, Henry T. Greely argues that the knowledge of the birds and the bees could cause another sea change in human reproduction. He outlines his predictions in an article on VOX and in his book entitled, The End of Sex and the Future of Human Reproduction.
Sex is obviously still the primary means of human reproduction today, but it may be going out of fashion because IVF is rapidly taking its place. So far only about 2.5% of American births are a result of IVF, but the numbers are growing rapidly despite high costs (about $15,000) and the painful procedures that are required right now. Attitudes have changed rapidly. Most Americans in the late 1970s when the first IVF experiments were successful thought that these “test-tube babies” were immoral. The official Catholic position still says IVF is immoral, but most people no longer agree. This will change further as new technologies promise to make it cheap and easy and it will allow prospective parents to eliminate genetic diseases as well as allow all sorts of other mind-blowing possibilities. Human sexual reproduction rates have fallen by more than half in the past half century. Greely argues that most of the rest of sexual reproduction could fall away in the next half century. He suggests that our grandchildren may come to see zero connection between sex and reproduction.