the challenge of getting from just the travel, hobbies, friendships to the parent sounds like such a worthwhile adventure. i don't know where the energy would come from to take care of a kid, but it seems selfish not to try.
it's not a weird "i want my genetics out there" type of thing. it's more like, i enjoyed the world enough, and now it's time to put my hand to the oar of rowing the next generation to the brim of adventure.
"adoption" is always a suggestion. but i've heard raising a kid is hard and raising someone else's kid is even harder. It's almost like doing society a favor to just raise one's own kid because it aligns the instincts with the task.