When one is female and has this predilection, she is referred to as a gold digger due to the assumption that she's after the older man's money. When a male has this predilection, he is referred to as a gigolo for the same reason. However, he can also be said to enjoy "the feel of a rusty trigger." This implies other motives altogether. Women usually do not get this second point of view option.
Now, that's real sexism.