Thanks for all the advice. However, I have tried every female over 18 and have set a male to parenting. Still only have 16 and my kids are about to be old enough to work, one baby about to "hatch" and there won't be any kids around to collect things. What am I missing? 11 out of 16 puzzles completed and all except two are on the second level - farming and engineering on the 3rd level. Do the men stop reproducing at a certain age too?