I don’t have a problem with his response.
“Nature/God” aborts many in the 1st weeks of birth. So many in fact, that most women fail to recognize they were pregant.
But, with the advent of “birth control”, it is questionable who aborts more...God or man.
"Killing a disabled infant ...[up to the age of 12 months or more]... is not morally equivalent to killing a person. Very often it is not wrong at all."
--Peter Singer
"I think that a chimpanzee certainly has a greater self-awareness than a newborn baby...There are certain circumstances, for example, where the newborn baby is severely disabled and where parents think that it's better that that child should not live, when killing the newborn baby is not at all wrong...not like killing the chimpanzee would be. Maybe it's not wrong at all."
--Peter Singer