Are you talking more skin tone or race? There's a huge diff imo.
Come to Nigeria, you'll see plenty of families like that. My ex was my complexion, but her sisters ranged from caramel to light brite. Her mom is light brite, her dad is somewhere in the middle.
I'm just saying when 2 people of different skin tones have children, the results can be all over the place.
Even my brother's children are light (he married a light brite Nigerian). He's the darkest one in the family, but, I assure you, he gives no fukks

.
But if you are talking a dark skin dude with someone of a
different race, that's different. if its interracial it always looks a little weird to me