Economics of Multiple "Babydaddy"

Here's a controversial explanation:

I noticed that uneducated mothers tend to have children from several fathers. I tended to blame this on their ignorance and shortsightedness, but apparently there is a very rational reason for this. Risk diversification.

Jinyoung Kim makes an evolutionary argument about mothers being ex-ante uncertain about the human capital of their children. In particular when the mother is less educated, she was to diversify the human capital risk of her children by having several fathers. In other words, monogamy is only a good idea if you are reasonably sure the children will all have good characteristics and are thus worth investing human capital into.

The logic works, especially for those whose children form their retirement.