"If someone has to go out to do work, the other parent got to look after the kids"
You would be right if in most societies women both did (and still does) a lot of work plus looking after the kids. It is true that most heavy works were performed by men (especially hunting, which gave social status as well...) - but women did a lot of agricultural work too, plus weaving, sewing, grinding cereals, etc. etc - as they could keep the children close (even on their bodies...), or have it cared by elder women.
It wasn't until a single man could earn enough to feed a family, and the industrial revolution reduced the number of hands required for some tasks, that women were left to care of the house only.
Patriarchy did exploit women for a long time - although it's really not much different from how apes behave.
Still many women worked in specific jobs even when machines became widespread, because more apt to perform them.
Anyway human children require a lot of parental care to grow - we just need to decided if we want a society were parents take care of them, or parent leave them into collective structures with people paid to take care of them. There are no other choice - but not having children - it's not compulsory.
Biting the hand that feeds IT
