Why (in my experience) do in laws favour their daughters children over their sons?
I have seen it time and time again. The only exception being my maternal Grandmother. I also have a MIL that just blatantly favours her daughters children over ours and it grinds my gears.
Please share your wisdom with me as mother to a boy and a girl I can't imagine ever feeling or treating their future children any differently in the slightest.