Don’t nobody @ me now, but the reason people want to have children – at its core – can be traced to one or perhaps all of the following things (in order of most common to least common):

1. Fear of growing old and having nobody to look after them
2. Desire to leave a “legacy” / vanity
3. Running out of things to talk about or fill time with / wanting some kind of purpose
4. Societal expectations
5. Biology / survival of the species

Re: the vanity in No. 2… people deep down really just be wanting to see a little version of themselves running around and shit.  Amirite?  Don’t lie now.