Why are sons expected to leave their family?

Depends on which partner has a closer bond to their family. A son is expected to get out on his own and support himself, and so find a woman to start a family with. A woman really doesn't need to prove she can support a family, because traditionally she hasn't had to. Also it is more assumed that a daughter is staying at home to "care for her parents" while it is assumed a son stays home to be a mooch. You cannot begrudge a man or a woman a good relationship with their family, and the couple will automatically gravitate to those they have the best relationship with.

Maybe that's how it works in your family, but not in all families. My parents gave me luggage as a high school grad present. A lot of women are made to feel just as bad for staying with their parents past a certain age, and a lot of men are not estranged from their family at all. Every life is different.

In general though, men do have more pressure to be providers. It's a holdover from a time when women couldn't even get jobs, and the only way they could move out was to get married. It's outdated, but things change slowly.

I don't know what family you live in, but in my world, "to each his or her own".....

It's only odd if a 50 something year old man lives with his mother and has been doing so for thirty years. As far as people in their 20's go? Well this economy sucks, and it's not that easy to strike out on our own without saving money, planning and having a stable job. It is what it is for both men and women.

I think the majority of people over 25, 26 live independently or with a spouse these days.

Personally I dont think that a guy in his late 20's or early 30's is a loser if hes living with his parents. I would think that hes just waiting until hes being thrifty, wants to make sure his parents are okay and is waiting until he finds a wife to move out & start his own family. Society dictates that sons grow up to become protectors, daughters (females) are to be protected & a man cant defend, protect, support or head his family if he's allowing his parents to continue to do it for him after hes an adult.

That's not how it is across the board. Especially nowadays, more and more young people/recent college grads are moving back in with mom and dad. To them, it's not so much an embarrassment. If you don't mind me asking, which country do you live in?

I don't actually know any women in their late 20's living at home. I was out of the house at 16+. In my 20's.. none of my friends were living with their folks. None of my nieces were living with their folks in their mid-20's and neither were any of their friends. None of my friends daughters were living with them after they were 21 or so.

Perhaps we live in different parts of the globe.

Because, you're supposed to be a MAN.

I think anyone over 22 living with their parents is a loser

Thats BS. Pretty much thats how it is for guys and girls where I live. Its part of growing up, thats how it should be