From a philosophical doctor:
At first glance, sexual reproduction is a puzzle, since each member of an asexually reproducing species can produce its own genetically identical young at a lower biological cost. However, sexual reproduction allows a more rapid reshuffling of the genetic deck, increasing the probability that some individuals will be well adapted to environmental changes. Because human beings reproduce sexually, the foundation is laid for sexual selection, the competition for mates of which Darwin wrote in such detail…
The writer Leo Tolstoy (1828-1910) presents a more broadly humanistic understanding of the purpose of sex. In “Anna Karenina,” often ranked as the greatest of all novels, sex provides the foundation for the family. Characters who treat sex as an adventure with no regard to family come to bad ends, while those who devote themselves to family happiness fare well. In Tolstoy’s view, the seemingly mundane joys of family life, made possible by sex, constitute the truest joys accessible to human beings.
Richard Gunderman, “What is sex really for?” at The Conversation
Darwin’s sexual selection (seen as an alleged massive shaper of evolution) has given rise to any number of naturalist legends, including—local favourites—the Darwinbird of Pop Science and the Clever Abortion Mare.
It’s such easy pop science on a slow news day around Valentine’s Day…
More to the point, Tolstoy is likely right insofar as family shoves other human beings directly into our faces for a long time and how we treat them matters a great deal. But that may be a very politically incorrect observation in these times.*
In any event, that approach is only possible because of explicitly human cognition. It probably doesn’t explain sex in the animal world where a variety of interactions that are not moral choices can be viewed.
Note: Some people cannot discuss these topics without giggling but they are usually—in some sense—roughly thirteen years old.
See also: Can sex explain evolution?
*Have a look, for example, at the way members of a local church in Toronto, Canada, reacted to the idea that a feminist should be allowed to voice her opposition to transgender policies that, she says, work against born women’s interests.
Remember that Trinity-St. Pauls is actually a church in Toronto:
Clearly, many traditions encompass a much broader range of views than they used to.