DS (16 months) has retractile testicles. Sometimes they're out, sometimes they're not. They're normally visible when DS is sitting in a warm bath.
So far I've not been too worried, as my understanding is that it's only a problem if they go up and stay up.
But - how long is it normal for retractile testicles to be retractile? When are they meant to stay descended for good? I'm a bit concerned that it might be possible for them to get stuck in the ascended position at some point, if this goes on too long.