This is a very difficult topic to debate, especially if you want points that favor the legalization of prostitution.
Prostitution is usually a crime as the act itself is considered demeaning to the prostitute and it is something that no prostitute would take up given a free choice. One point why prostitution should be considered like any other profession is the following point raised by a prostitute in her book
The truth for me and many sex workers I know is that we chose sex work for money, independence, freedom and dignity. If you can't understand the last word, dignity, then you are mired in a viewpoint about sex in general, and sex and women in particular, that this patriarchal society wants you to buy.
The prostitute and the customer can be considered to be two consenting adults engaging in sex. There is nothing here that is demeaning to the prostitute.
It is also essential to clearly discriminate what would come under legalized prostitution and what would be strictly excluded.
As prostitution is currently illegal, it is carried out by cartels that find ways to conceal their activities and to gain the most usually use the services of children and women who cannot resist due to various reasons. The prostitute today is as much a criminal as the customer.
If prostitution were legalized and strictly regulated, it could be ensured that only those that have registered themselves can offer their services. Customers would also not be committing an illegal act by accepting their services. They wouldn't have to approach prostitution cartels for the same and sexually abuse children and adults not willing to do the work.
Legalized prostitutes could be tested for STDs and only those who do not have any diseases allowed to continue only under the condition that they use adequate protection to keep themselves safe.