Request- Family Tree for Incest

[LeeLeeG2]

So a pet peeve of mine is that when you have an incestuous family in the Sims is that the family tree eventually starts dropping relationships and Sims end up with blank squares representing their parents. 

 

Could one of you amazing modders possibly figure out how to keep this from accruing?

 

Or make something that will accurately track a family tree with children from incestuous relations?

[Mysterious1968]

Good point. The Family tree function doesn't handle incest very well.

 

I once tried to see the limits of the unmodded Family Tree function. so in CAS I made two brothers, then I made a mother and daughter (unrelated to the brothers). Each of the women had a child (CAS function) by each of the brothers, giving a household of eight. In the game, the individual family trees of each of the Sims was an incomprehensible mess, not even showing the relationships betweeh half the household.

 

Family Trees in Sims 2 could handle this level of interfamily messing-around, and even actual incest. Why can't the same function in Sims 4?