Both my woman and man have had 1 baby boost each. After reading the post in the spoiler tag above, I decided to try it out in a less extravagant way.
In case you're interested, I bought 3 extra baby boosts. I gave all of them to the woman, and got them to try again. The woman was 49 (gray hair!) and the man was 47. I'd tried for at least 10 times before this, to no avail. IT WORKED ON THE 1st GO! I now have new kid, Nirvana!