Does "all firstborn males" mean if the person is the oldest child in the family or is the male required to fast if he has an older female sibling?
It only applies to sons who are the oldest issue of his mother's womb from her first pregnancy. If he was born through a C-section, he doesn't have to fast or if his mother had a miscarriage in a previous pregnancy, he doesn't have to fast. Also, a son is still required to fast if he has older half siblings from his father since first born is counted from the mother.
if the woman miscarries, and the baby was female. Then wouldn't a male baby born normally , be considered a first born male, and have to fast on fast of the first born?
in cases I know of, the woman does not talk about the miscarriage. the first born son fasts.
it seems rather cruel for the mother to be reminded every year that her son isn't fasting because she had a miscarriage so the live son isn't really her first born son..
I was not aware of any of these details like caesarian section, or a miscarriage, affecting whether one fasts. or more oddly, whether one is considered a first born.
what is your source?
you should always include sources..