The Sims 4 has less advanced genetics than previous Sims games?

I think genetics are kind of interesting in this game. The first time a Sim had children in my game, they were non-identical twins.
The parents were: a male with red hair and brown eyes, and a female with red hair and blue eyes. The children were: a female with red hair and brown eyes, and a male with black hair and blue eyes. Kind of strange but interesting.