Human reproduction truly is the irresistable force meets the unmovable object. The ‘irrestistable force’ is ‘survival of the fittest’, and the ‘unmovable object’ is ‘reliably putting together something as complex as a human being’. There are so, so, so many things which can go wrong in human reproduction, that it’s astonishing that it is so frequently successful.
Here a partial list of the links in the chain of human reproduction:
– Sexual attraction
– Sex drive
– Sexual attractiveness
– Supporting the growth of a fetus …
– … without killing the mother
– Romantic attraction (to keep people together long enough to care for a child for a few years)
– Romance drive
– Breastfeeding (or altenatives)
– Intent to biologically reproduce (this is more cruial when effective birth control is available)
Many people who want biological children do run into problems in at least one of these links … because complex processes have high rates of failure.
At the same time, evolution pushes reproduction pretty fiercely, so that many people who don’t want biological children sometimes end up with a pregnancy. The only birth control method that comes with a 100% guarantee of no pregnancy is castration (though interuterine devices, vasectomies, and in some circumstances, abstinence, come pretty close to 100%). Most birth control methods try to weaken or interfere with the chain – only castration breaks it.
It is suspected that men in my father’s family tend to have low sperm counts, and my own father was declared infertile as a young man. The fact that men in my father’s family tended to have few or no children even without birth control is evidence. Yet some men in my father’s family obviously managed to have biological children, including my ‘infertile’ father – low sperm count does not mean zero sperm count. Even with that loose link in the chain, the other links in the chain kept biological reproduction happening – for example, according to the comments of various people, handsome looks (i.e. sexual attractiveness) also run in my father’s family.
Based on the history of the women in my family, I most likely have at least an average level of fertility, possibly higher, and right now, my level of sexual attractiveness is high. In my case, the loose links are my lack of sexual and romantic attraction, as well as low sex and romance drives. I can, if I want to, compensate for this link with willpower (i.e. use the ‘intent to biologically reproduce’ chain) … but most people don’t have to use so much willpower to get the biological reproduction process started.
Looking at the system in abstract, it is a marvel. The chain compensates for the links which will inevitably come loose in a complex system by pushing for as many strong links as possible.
Of course, this isn’t entirely abstract for living people. It shapes our society, our relationships, our bodies, and our feelings, in short, our existence.