What is funny about that?

A famous heart specialist doctor died and everyone was gathered at his funeral. A regular coffin was displayed in front of a huge heart. When the minister finished with the sermon and after everyone said their good-byes, the heart was opened, the coffin rolled inside, and the heart closed. Just at that moment one of the mourners started laughing. 

The guy next to him asked: "Why are you laughing?" 

"I was thinking about my own funeral" the man replied.

"What's so funny about that?" "I'm a gynecologist."