Not directly mentioned in the article, but relevant: Richard Dawkins, in at least one of his books, discusses why dads don't put in as much child-rearing (in many mammals, for example). The evolutionary incentives for fathers and mothers are the same (eg they have equal stakes in the genes being propagated). 2 categories of reasons. (there may be more)
- Fathers (depending on species) can't be confident a given child is theirs. Mothers can be confident due to giving live birth. Fathers have a lower incentive to care for a given child, since expending effort on offspring that's not yours is evolutionary detrimental; everything has an opportunity cost.
- Mothers have a much higher investment in the child from the moment of conception: Due to the extra food they must consume to nourish the embryo, the effects of pregnancy etc. By comparison, sperm is cheap. Neither parent wants to let the child die due to lack of care, but the fathers are in a better position to call the mothers' bluff than vice versa due to the sunk cost.
- Fathers (depending on species) can't be confident a given child is theirs. Mothers can be confident due to giving live birth. Fathers have a lower incentive to care for a given child, since expending effort on offspring that's not yours is evolutionary detrimental; everything has an opportunity cost.
- Mothers have a much higher investment in the child from the moment of conception: Due to the extra food they must consume to nourish the embryo, the effects of pregnancy etc. By comparison, sperm is cheap. Neither parent wants to let the child die due to lack of care, but the fathers are in a better position to call the mothers' bluff than vice versa due to the sunk cost.