Doctor visit

So this older man is married to a younger woman, and she is always complaining that he can not keep up with her in the bedroom. So one morning she asks him to go so the doctor to see if he can help him out. He goes to the doctor and tells the doctor: Doc I'm married to a younger woman and I can't keep up with her in the bedroom, can you help me out? Doc says we have to run some test but I think I have just the right thing for you, the man says what is it? Doc says its a monkey gland, let me run some tests and see if your body will take to it. Hours later the doctor says ok all done, it will work but its gonna cost 100 bucks, the older man says ok, so that night the man goes home and wears his young wife out, the next morning she ask him how he did it and the older man told her the doctor put a mokey gland in me it costed 100 bucks, so she goes to see the doctor to ask him if he could help her to keep up with him now, doc said let me run some test to see if your body will take to it, she says ok, so the doctor examines her and says ok it will work but it will cost you 200 bucks, she said why 200 it only cost my husband 100 the doctor said yea but you need a whole new monkey.