How Far Have We Fallen
The following account as far as I can tell is really quite a typical one.
When I was sixteen it suddenly occurred to me that I would not live forever and I immediately changed my mind about having children - I wanted to have people to raise and pass on my views and teachings for after I have died, more than anything else. I guess I see it as a natural consequence of the survival instinct - just like I want to survive in the short-term future, I want to eventually have successors. The most legitimate and effective way for me to do this is to meet someone who I am attracted to who also wants children.
Since I was about fourteen I've had a more primal desire to have intimate relationships with women. I came to the conclusion that promiscuity is not sensible, so my attitude was that I should restrict my prospects to people who I could imagine myself dating. This desire and attitude has, for the most part, not really changed since then.
If I remain single my entire life then neither of these will be satisfied and I foresee severe emotional problems later in life, as are common to middle-aged single men, hindering my progress in other areas of life such as my career.