Why do people have kids?

So i was thinking aloud, "Is it instinct when I had Navis, or do I really want kids?"

The reason I asked this is because I did have a passing thought of not having kids. Well actually with Navis it's just sorta happened. Never intended to get pregnant but wouldn't object if I do.

It has always been a tricky question.. Do i want kids? What to do with them anyways? Why do we have to have kids? (Of course we don't )

Our body are engineered to have kids. You have the urge to have sex and sex = kids. Of course nowadays there are contraceptives but they can be so tedious. E.g. with pills you have to take one every day at the same hour. IUD doesn't always work.. Condom is well I just hate condoms. See.. You get this feeling that it's unnatural. No i am not against family planning i am for it. Couples should plan when they want children. And if you don't want any, then go ahead.

So anyways.. Then I have Navis everything in me just switched to mommy-mode. He becomes the most important thing in my life and right now everything I do revolves around him. (Sorry Iko, mom & dad).

So, is this just instinct? Part of our survival thingy as a species? Can you want kids the way you want a particular dress or shoes? (Yes i guess you can).. I wish i could ask my DNA..Am sure this survival instinct is embedded somewhere in our genes: "Is having kids still necessary when human population is way way too much?"