Haemophilia is an X linked disease. Ie its on your X chromosome. Women have 2Xs, men have XY. If a man gives a child his X, they have a daughter (mums always give Xs), if a Y, the child is XY (son).

Men are XY, so if they have a daughter, the daughter will definitely get a faulty X from dad. Theres one X, and its faulty wrt haemophilia. But most likely a healthy X from Mom. 1 healthy X is sufficient to be very normal. 2 bad Xs normally don't happen - pregnancy often doesn't reach term

My Mum's father had it , of his 4 kids, the 3 girls are all guaranteed to be carriers (1 good X 1 bad).

The brother of my grandpa is a man, got the Y from grandpa..i.e a haemophiliac male has no chance of giving it to his son. But all the daughter's are carriers.

So haemophilia ended for most of my wider family - my uncle and his kids can't have it, one auntie never married, 1 auntie was a carrier but had 1 daughter (almost 0% chance, but 50% of being a carrier...but she ended up not even being that), and 1 son (flip a coin on getting the good or bad X).

In my case, my mum had 2 sons...50% chance for each of us having it. We both do.

It's really not that pervasive as it skips a generation every time.

None of any kids i have, will have haemophilia. If i have only sons, Haemophilia ends for any of my future generations. If i have daughters, each will certainly be a carrier, but only have a 50% chance of making their own children a carrier (girl) or a haemophiliac (boy).

It depends on the therapy. In this case, no, it’s not likely to target sperm or egg cells specifically. This sort of treatment is far more about reducing or eliminating symptoms in someone already affected than stopping transmission to offspring. That sort of discussion can get very dicey very quickly. The word “eugenics” comes to mind