Biological desire for children

We don't seem to have a biological desire to have children.
We have a desire to have sex and we don't need any additional desire to have children, since having a children is a by-product of sex. But of course this has changed thanks to birth control.
Once children are born we do have biological incentives to take care of them.
Whatever desire people may feel to have children seems to be created socially. Talking about the urge to have children and refering to it as "biological clock" is misleading, the urge is social.
== References ==
https://theconversation.com/maternal-instinct-and-biology-evolution-ensures-we-want-sex-not-babies-46622