This story is an old one, popular with zoo veterinarians (Im told).

A certain zoo had acquired a very rare species of gorilla. Within a few
weeks the gorilla, a female, became very ornery, and difficult to handle.
Upon examination, the zoo veterinarian determined the problem: she was
in heat. What what to do? There was no male of this species available.

While reflecting on their problem, the zoo administrators noticed Mike,
a JEDR responsible for cleaning the animals cages. Now Mike, it was
rumored, possessed ample ability to satisfy any female, and he wasnt very
bright. So the zoo administrators thought they might have a solution.
Perhaps they could entice Mike to satisfy the female gorilla. So he was
approached with a proposition: would he be willing to screw the gorilla–
for five hundred bucks? Mike replied that he might be interested, but
would have to think the matter over.

The following day, Mike announced that he would accept their offer,
but only under three conditions: First, he said, I dont want to
have to kiss her, and Second, I want nothing to do with any offspring
that may result from this union.

The zoo administration quickly acceded to these conditions, but what
could be the third? Well, said Mike, Youve gotta give me another
week to come up with the five hundred bucks.