9 Answers

No.

Not a good idea, if you live your life like that you will need those big wheels.

Yes. I know 2 brothers who have 1 sister.

Why would you want too?

YES.  Two sons can have a relationship with their mom. 
I know that's not what you're referring to, though, and my answer to THAT question is a question to YOU:

Are you sure you don't mind YOUR girlfriend being someone ELSE'S girlfriend at the same time?  Think about it very carefully, because if you DON'T mind, then you need to look for a woman who you DON'T want to share.  

No. one guy can have one girl and the other guy can have someone else and it will be fair of course.

They can try but there will be jealousy, envy, disrespect, non-friendly discourse, all that bad stuff to go on....

Not if the girl has respect for herself.

WHY NOT .The same the otherway around If that`s what they want .bet its happenen "NOW" All over the Globe .