Summary from Google Books:
Better Never to Have Been argues for a number of related, highly provocative, views: (1) Coming into existence is always a serious harm. (2) It is always wrong to have children. (3) It is wrong not to abort fetuses at the earlier stages of gestation. (4) It would be better if, as a result of there being no new people, humanity became extinct. These views may sound unbelievable--but anyone who reads Benatar will be obliged to take them seriously.