Having done what I consider a lot of third party research (I wasn't going into the sex industry for first or second party research), I feel I have an idea of the sexism in the sex industry. Most of my research focussed on pornography, as opposed to prostitution, so theat's wherre I'll focus.
There are instances of sexism to both sexes, but in different ways. For women, sexism occurs in the meriad of ways in which they are paid to act. The more extreme, the more payment. However, due to the nature of the work, most actresses will be forced into these types of situations. When they start, they can make alot of money on very basic things. As there carrer progresses, however, the people will have already seen them like this or that. As such, if they want to keep working, they have to do something new. This works more for videos, though there are model shoots of a similar variety. As for prostitutes, most work for pimps who take most of there profit, and if they don't, some guys don't feel the need to pay. They are treated badly by both pimps and customers. If they are lucky enough to work in a registered brothel, there are precautions taken to ensure there safety, but even so, the conditions they work in can be deplorable. And once again, the more extreme they are asked to act, the more they can charge.
Male video pornographers must have the following attributes: Well endowed (except for the few for that kind of fetish), ability to maintain an erection for extended periods of times (sometimes hours), and the ability to ejaculate on cue. This is easier to achieve since the invention of viagra, but is still difficult. Any man would understand the risks involved in such strain. On top of this, male pornographers only make (usually) 40k a year without doing gay-for-pay videos, compared to women making 100k-250k a year. An actor looking to make more money will usually do gay-for-pay videos, which runs the risk of labelling them as a homosexual, and subject to homophobia.
As for prostitutes, male prostitutes don't normally work for pimps, on the assumption that they can take care of themselves. Not only that, but they can't flaunt their business like female prostitutes, and take a risk every time they try to pick up a job. And, once again, they get apid less unless they go gay-for-pay.
Most people focus on the sexism seen against women here, because it's been seen in other industries. It's all well and good that we want to eliminate sexism in the workplace, but we shouldn't fall into the assumption that only men can be sexist. What this industry needs isn't more restrictions and laws, but better working conditions, and more equality. A better understanding of this industry would go a long way as well.