"It is, therefore, appropriate for Christians to ask themselves how getting married or, if married, having children will affect their share in that vital work. During all this pre-Flood period, Noah's sons and their wives had no children." Watchtower 1988 Mar 1 p.19

"Although Noah's three sons were all married, none fathered children until after the Deluge. While this does not imply that it is wrong to have children today, many Christian couples decline to have children so as to become more fully involved in the urgent work that Jehovah has given his people to do. Some couples have waited for a time before having children; others have decided to remain childless and consider the possibility of bearing children in Jehovah's righteous new world." Watchtower 2000 Aug 1 p.21