Is it ok for my brother to date my girlfriend's sister

I know that in the US if you and your brother wanted to marry sisters you could.I believe that is what your trying to ask?

I think it's OK. But if they really start relationship, you will feel a little embarrassed, especially when they have a quarrel or something others. However, in a whole, if they really love each other, you should encourage him to seek for his true love.

I would say "No". Don't encourage it because what if they find that they are truely in love and want to get married. But then, depends on how strong you and your gf are. It's a race to see who gets married first, really. As soon as one of you gets married, it makes the other couple "brother" and "sister" and that's too close to the family line.

I guess there's nothing wrong with that. Though this happens so rarely, I don't think we have the right to condemn siblings who fell in love with somebody from the same family. I am a catholic, but I haven't heard any issues regarding this matter yet. Well, if things go smoothly between you and your girlfriend, and your brother and your girlfriend's sister, then it calls for a celebration. :P

I don't see why not you are not all related in ay way ?? So as long as there are no competetion between you lot it should be ok. It will be the girls who will share every thing they feel about you guys if they are close sisters and may compare if thay are like that but if not it could be great.

there's nothing wrong about your brother ( is he a younger brother? ) dating your gf's sister as long as his intention is clean and will not just play around, as it'll have an effect on you if he does..

Hey ! In my oppionion you shouldn`t even worry about this .. because in your gf`s sis`s place could`ve been any other girl .. so just let them get to know eachother better .. they`ll know if a relationship should be started or not .. as he didn`t interfeer in your relation .. you shouldn`t do that either .. no matter the person he wants to be with .. :)

If he likes the girl, then let him do what he wants to do. You have your own life and he had his own too. I mean, just because he's your brother doesn't mean you have to forbid him. For me, it must be cool if you're all connected to each other so you can group date or something like that without the feeling uneasiness. But if ever you forbid your brother, then let me have that pretty girl instead. Haha joke! - Ron Reyes www.ronreyes.co.nr