I retract my earlier statement about nieces or nephews. An heir can move into a house where there are children as long as the children do not belong to the heir or the new spouse. Once you become the girlfriend/boyfriend of the new spouse, you will be able to see into their household using the family tree to find out if there are potential children by them in the next house.
ok I know we are supposed to send all babies that result from getting abducted back to their homeworld, but what if say we were to move out the current heir during a pregnancy, would that be breaking the rule since the pregnant male would no longer be in the household...
This is in discussion right now amongst the team. As soon as a decision is made, I promise you'll hear from one of us. I just didn't want you to be left hanging so thought I'd say something now.
Edit: Should the circumstance actually happen that the heir's requirements just happened to be satisfied at the same time as an alien pregnancy - yes you can go ahead and have your heir move on. Only in the event that the heir has actually fulfilled all of his/her requirements. That alien child born in the former household however can never be in any future household of any heir as it's considered a former household member.