Good question, I personally think that we all have this survival instinct, which would mean that our prupose as a species (just like any other) is just that, to survive and perpetuate our species. I think that's why there was so much pressure in the olden days (and still in some traditional areas) to get married and start a family: to keep the species going.
But since at some point we developped brains, thought, "morals" and all of that, we started reflecting on that. And at some point it actually became a choice to have children or not, with contraception, abortion, homosexuality (if no adoption or medically-assisted procreation), or just deciding to live alone. But once that is a possibility, it means that for that person bringing a child to this world is no longer a priority, but he/she still needs something to keep him/her going. That's maybe why people invest so much in their jobs, hobbies and whatnot, to kind of replace that "procreation" thing. Basically, they/we need another direction. Even more so now, in a the first period in which this generation (30 years old) have it somehwat worse than our parents, not on strict economical terms but as a perpective, people believed that the future would be bright just 20 years ago, but that's not what most of our generation think. so the question of procreating in this world is a very real one.
Other than that? Enjoy life I guess