Well first off here's the heir Prudence Kingsley as a teen after a CAS makeover (all I did was change clothes and the hairstyle and added makeup). I think she's pretty for an in game sim.
And the main point of this post. Prudence brought her half-sister Johanna home from school. Here's the half-sister talking to her half-brother Henry as Henry's mom looks on.
Here the two sisters are talking while the dad looks on. He's the father of both children. Basically, before he married my founder Amanda Kingsley he had a girlfriend Betty that he got pregnant and this daughter Johanna was the result (the girl on the right). Now Johanna is a teen like the children of my founder so inevitably they met her at school.
I think they really do look like sisters. The half-sister is in the blue.
The heir Prudence is in the purple. But to me they really look like they could be sisters. lol.