One night John is in the bar drinking heavily. The bartender is curious why John is drinking so much.
"Why are you drinking so much?" He asks John.
"I've just found out that my father likes guys!" John replied.
"Fair enough." Said the bartender handing John another drink.

A week later John is back drinking heavily again.
"Why so much?" The bartender asked.
"I just found out that my brother likes guys!" John said.
"Fair enough," The bartender said and walked away.

A month later John is back yet again and drinking more than the previous times. As the bartender walked up John said,
"I just found out my other brother likes guys!"
"Sheesh John does anyone in your family like girls?" The bartender asked.
John nodded and replied, "My sister does"