Why kids are named after dads

Feminists sometimes say that it is unfair that they are expected to take their husband's name, but men do not change their names when marrying. Millennium-old customs usually have reasons for them, that would be obvious if you were not brainwashed with feminism.

SatoshiKanazawa explains Why Children Must Inherit Their Last Names from Their Father, Not Their Mother

Patrilineal inheritance of family names, where children inherit their last names from the father, not from the mother, evolved as a social institution as one of the mechanisms to alleviate paternity uncertainty. Like all mammalian males, human fathers can never be completely certain of their paternity, but, unlike most mammalian males, they are asked to invest very heavily in their offspring. Therein lies the possibility of cuckoldry – unwittingly investing their precious limited resources in the genetic offspring of another man. Males of only a very few species in nature (humans, and many avian species) face the danger of cuckoldry because male parental investment among these species is high. Males of most species in nature don’t care if they are really the genetic fathers of the offspring that their mates produce because their male parental investment is limited to the sperm deposited inside the female during copulation. ... As a result, males of most species in nature do not experience sexual jealousy, only humans and birds do.

Males of these few species – human fathers in particular – therefore need to be reasonably convinced that they are indeed the genetic fathers of their putative offspring before they would agree to invest heavily in them. Both nature and social institutions aid in such an effort. There is some evidence to suggest that newborn babies are born looking more like the father, not the mother (because maternity is always certain and mothers don’t need to be convinced), and mothers and maternal relatives often allege paternal resemblance of babies in order to assure their fathers that they are indeed their genetic fathers and thus they should invest in them. (Remember, mothers and maternal relatives don’t really care what the genetic truth is, because they are guaranteed to be equally related to the children whoever the genetic father might be.)

Patrilineal inheritance of family names is another social institution that emerged to convince the fathers of their paternity, by saying (if social institutions have a vocal cord) “The baby’s really yours, because it has your last name!” Russians take it one step further, by giving their children – both their sons and daughters – middle and last names after the father.

So the kids are named after the father, as a way of formalizing his investment in them. The mother is already invested. She does not have to change her name, but she usually wants the same surname as her kids, so she adopts a married name.