The only answer I can think of for the "Why can't I" questions is that nobody's written it yet.
What's the Bio-Science centre for?
I assume it's something to do with what Briget said about improving Steele's fertility/virility, but it doesn't have any content yet.
Given what's in the code, I think there were plans to add Yammi as the nursery's head chef if she wasn't on the ship (and possibly some other condition(s)), but there's been no word on that that I know of. Savin was also planning for Briget to be sexable, so that might be somewhere in his massive backlog. I don't know of anything other than that, but I presume someone is working on some new pregnancy content somewhere.
So far, the only interactions are:
Observing or playing with kids (half-zil, half-milodan, Ellie's, half-laquine, Zephyr's, Sam's, Mirrin's, Gel Zon's, hilinara, Quaelle's and water princesses can be visited; the other ones on the specialist deck can be observed (cuntsnakes, cockvines and hilinara can be observed in detail), plus a small Halloween event*);
Some of their parents (Zheniya, Ellie, Zephyr, Roxy, Sera and Riya) (some with their kids, some by themselves);
All of Briget's content; and
Re-recruiting some crew members (Sera, cured Reaha and Amber) if they've been kicked off the ship.
*This event includes (assuming appropriate kids exist) Zheniya, Sera and their kids, Briha's first two kids, half-milodans, half-korgonne (if there's also a half-milodan present), cuntsnakes, rahn, bothrioc, water princesses and Yammi (if she's been recruited).
