Women can handle a plow and produce more food than a man's small flower-garden, too.
Besides, poor farmers, who couldn't afford a horse or a cow/ox, they had to both push and pull the plow, so both man and woman were needed.
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If one in the couple dies, the family's ability to feed itself will suffer less if they used to help each other out, with most or all chores.
If the woman is disabled or dies, the father will have a tough time feeding infants, and teaching them to walk and talk on his own. Thus both parents are just as important to the survival of the family and valued as much.
In hunter-gatherer societies, for the long dangerous hunts, they probably needed most of the young and strong, regardless of gender. The old and the children stayed behind, catching smaller animals with snares and gathering fruits and vegetables. Also, if the relatively few (a lot of time and energy were invested in them, so they couldn't happen too often) long dangerous hunts didn't bring in any catch, they could still survive on the more stable inflow of small animals, fruits and vegetables. Everyone is still important and survival is greater if everyone help each other.
Regarding economic value you produce: Today in most of the Western world, children only cost money during their first 18-20 years. Healthcare, schooling, sports, training and food goes into them, and not much comes out. If social value is only tied to your economic value produced, we should stop reproducing NOW, and just bring in adult immigrants, who are already trained and educated, and who can start working right away, after just a few weeks of language training.
