Can actually be done without any inbreeding. For instance, if a man has children with two women who are sisters, the children would be paternal half-siblings and maternal cousins. Used to be fairly common when arranged marriages and dying in childbirth were normal. Wife died, but the marriage ties are important so you marry her sister.
Both can be true! (Being siblings and cousins at the same time, requires bit of inbreeding ofc)
Can actually be done without any inbreeding. For instance, if a man has children with two women who are sisters, the children would be paternal half-siblings and maternal cousins. Used to be fairly common when arranged marriages and dying in childbirth were normal. Wife died, but the marriage ties are important so you marry her sister.
An ex of mine had this situation!
Her mom had one guy, got 2 kids with him and divorced him for his little brother, with whom she had another kid.
I bet he liked coming home to his neph-son.
I’ve got 2 sister cousins. My mom’s sister was declared unfit, and my parents legally adopted.