Two guys, one girl.

Two mates were bonking the same girl at the same time, and they were
greeted with the sad news one day that their common squeeze had got
knocked up.
Having no way of knowing which was the father, the two mates
chipped in and sent her out of town to have the little baby.
Several months passed without either of the mates hearing from the girl,
so one of them decided to find her and get some news about the pregnancy.
The next day, the other bloke got a call from his mate. "I've got some good
news and some bad news," the mate said on the telephone.
"Well, give me the good news first," replied the other.
"The good news is that she's fine, and she had twins," came the reply.
"And the bad news?"
"Mine died"