When I was a teenager (1970s) there were always lots of jokes by people like Les Dawson about mothers in law. It therefore took me a bit by surprise that women seem to have more problems with their mothers in law than men do.
After my parents divorced, my father married a widow with sons. My siblings (all female) and I got on ok with our new step mother, but she had a poor relationship with all her daughters in law. Just as a small example, my father and stepmother always spent Christmas with one of my family. They were never invited by her sons.
I get on well with my mother in law but, when I read some of the threads on Mumsnet, I confess that I am relieved that, with two heterosexual daughters, I will never have a daughter in law of my own!