Mom treats sons different from daughters?

I've noticed that my mom acts different with my brothers than with my sister and I. My brother came home with hickies on his neck, he's 21...nothing wrong right? I remembered living at home I was 23 at the time. I did the same thing. My mom grabbed a stick and started to beat me with it until it broke. My brother spent the night out, came home the next day. I tried the same(I was just down the street literally talking all night with my bf, I know it was wrong of me to stay out but I tried explaning) and once again she beat me with the stick until it broke. Just goes to show boys are allowed to do whatever. My mom said that we can get pregnant that is why she did what she did. My sister is 32, she just lives downstairs from us(she bought and paid for it) went out on a date with a guy from high school. My mom started getting upset and I know as a mom you worry but not to the extent of beating one child and then sparing the other. My brothers are 17-30. My mom is still doing their laundry and whenever i tell her she's being an enabler she says its the women that's going to have to deal with it.