1. Female blood did not count nearly as much in social climbing due to the overall status of women; a noblewoman who married a commoner retained her own title, but her children would be commoners. That's why there's such obsession with women making "good marriages" with men of suitable social class and wealth.
2. Homosexuality was closeted to the point that someone who was accused of it had to leave the country or (if in the military) eat his gun. The merest accusation could destroy careers. Rowling isn't nearly that bad, but as I said in an earlier comment, I don't think it's a coincidence that she married off the two characters a lot of people were reading as queer (Lupin and Tonks) and had them die in a safe, heterosexual relationship after they'd proved their heterosexuality by having a baby.
Re: (2/2) Further questions -- really just questions
2. Homosexuality was closeted to the point that someone who was accused of it had to leave the country or (if in the military) eat his gun. The merest accusation could destroy careers. Rowling isn't nearly that bad, but as I said in an earlier comment, I don't think it's a coincidence that she married off the two characters a lot of people were reading as queer (Lupin and Tonks) and had them die in a safe, heterosexual relationship after they'd proved their heterosexuality by having a baby.