Now I´ve done it too...
Vattnadal told us - in Swedish - that she put the old boy of nearly 2 years of age in the cage with old ladies. No one of them could have any babies… she thought… 
But she found babies in the house anyway…
I got two mouse brothers I mated with separate doe some times, and only one of them seamed to work in breeding. He also turned a bit dominant toward his brother so the more gentle brother moved in with young males. It only worked until the young male turned dominant and started argue with the soft male. So I thought, well, soft and not dominant… so gentle, he´s out of testosteron… He can move in with the ladies…
So he did… a couple of weeks ago… and now… he´s got testosteron!!!
But since he´s one of my best males and such a beautiful color as pe silver and got a thick texelfur it´s not sooo bad. I just hope the old ladies don´t go sick…
Oh, what a pleasent surprise
For all of you… 

I´ve got 2 little agouti texel girls in my "old-lady-and-gent" cage! Didn´t believe my ears when I heard baby-squeaks. My youngest babies are over 2 months old…
MVH Elin
Medarbetare på spetsar och urhundar. VD på Draghundcenter

Yeah and when I put a 8 month old doe (already been mom once) with boys in the end I haven't had any babies
(not the males' fault anyway…).
I hope everything will be fine with your mummies-to-be 