To discuss sex workers in Ancient Rome is to part with our ideas and ideals of the modern view of sex work and sex. For in Ancient Rome, sex work was a vital part of both the economy and the social structure. It was an accepted, and considered necessary, part of society, and every gender could be found in the profession. With that being said, many sources cite women (likely cis women as we have little evidence of sex workers outside the cis male/female binary) were in the majority. Regardless of gender, sex workers — especially with Rome being a patriarchal society with a strong emphasis on the masculine — it was the “receiver” that was considered the weaker, lesser, and/or more effeminate of the participants. Cis women, within the strict gender roles, were naturally assumed as thus.
Here are some resources on the various areas and types of historical sex work. I suggest picking one area that interests you as it can be a bit overwhelming. These resources were collected by the Knowne World Courtesans.