Ten Gen dynasties can be frustrating.
So, after five generations of not being able to get mltiple birth despite trying for them in the ley-line lot (and anyone else whoo tried there had twins, only the heir didn't), I finally got them without trying. In the only house where I had only 2 free slots, and the other should have been used for someone's else baby.
And, to add to this, despite the pop music surrounding the future mom, first born is a boy. (and second is a girl, obviously.)
Well, the good news is that gen 8 is here and got very lucky with random traits.