that a child should always ahve their biological fathers last name if the mother knows whot he father is. it doesnt matter that the father is not a part of the boys life at all, i think family names should never be changed you will always be your fathers blood no matter who adopts you or who you marry. i personally regret changing my last name after i got married, i will be changing it back to my maiden name actually. i dont know...thats just me, i dont believe in changing last names of kid even if you adopt them or changing you last name to y our husbands either.