A great joke

It mentions sex, so be warned, if some reason, you don't want to be exposed to sex.

Bob's a big hit with the ladies at the nursing home, because there are only a few men. Doris asks Bob out on a date.
Bob: I can't go out on a date with you. I'm going out with Gloria.
Doris: Well, I can take you out another time.
Bob: I'd prefer to go out with Gloria.
Doris: Why?
Bob: Gloria will take me out to dinner.
Doris: I'd be happy to buy you dinner.
Bob: Gloria will take me to a movie afterwards.
Doris: I can take you to a movie.
Bob: Well, Gloria will hold my penis during the movie.
Doris thinks about this minute then says "I can do that too."
Bob: I'd still rather go out with Gloria.
Doris asks frustrated, "What does Gloria got that I don't?"
Bob: Parkinson's