This has been somewhat of a quiet problem within the JWS going back decades, actually the insinuating push to not have children in the organization goes back to the 1930's and all through the last century.
I've known many JWS including people in my own family who were quite adamant that the would hold off having children in this system things.
Why did the WTS do this is because the leaders wanted as many people as possible distributing their literature, showing their dedication to Jehovah's will and purpose as it were. By the way this system of things is still coming to an end soon .
We really mean it this time