So, the lamb unfortunately can't partake in hanky panky in the mating tent, but here's a hypothetical system that might sort out some of the issues that people have been speculating upon.
MATING
Treat the lamb like a normal follower when it comes to the initial mating. Let them get rejected by their followers if they dont hit the right percentage chance. Some people have suggested making it a follower questline that the lamb has to complete to woo a follower in the first place. So, its really an effort.
TRAITS
When it comes to traits, I think the lamb should have none, save for one that I'll get into later, so its actually a detriment to mate the lamb because you only get the traits of the follower and the random traits. It'll more be for story.
This is more a fun suggestion; but give a 0.1% chance for the kid to also be a lamb. Make it so this follower form is unobtainable normally, only through breeding. This can be tied to the trait I talked about earlier... 🥁
'Child/Descendant of the lamb'
THE ACTUAL KIDS
I think the lamb kids are completely normal followers. No need to complicate things. Maybe they've got just one special interaction. The only thing they'll share in common; is the descendant of the lamb trait which is always passed down to their offspring and so on, that is the nature of the trait.
Descendant of the lamb makes it so they can never mate with the lamb or descendent which stops the incest issue that people bring up. (I know its a game, but incest still icky people; come on). And also incentivises you bringing in cult members from outside to keep breeding.
Final word
I dont know how feasible this all is, given we're not privy to the design program of the game. End of the day, i like the update and this was just my attempt on how to bring in a feature a lot of people were hoping for.
Please let me know how you'd improve this system or if you think its unneeded at all! 
I was putting all kinds of different combinations into the mating tent until I found out it is just random 






