Last name

The father is the father married or not. The baby should carry the fathers name. If they don't get married the baby should still carry his name, he is the father. Now making a baby doesn't necessary make you a "father", it takes being completely in the child's life with loving care and responsibility. Who knows how it will go married or not, there are still some pitiful slugs out there. Also, John should mind his own business. His " child " is 40 years old, just give her support and STFU.