One of the major philosophical justifications for laws making sexual services (or the use of these) illegal is that prostitution is, intrinsically, a violation of human dignity, especially of the human dignity of women. Paying a person in order to accomplish a sexual act upon her or to have her accomplish a sexual act upon oneself is, so the argument runs, using her as a mere tool for sexual gratification, and this is so even if we suppose – what some claim to be impossible – that the person in question offers her sexual services voluntarily and without being forced or coerced. Consent may be transformative in many instances, but it cannot transform a prostitutional act into something compatible with human dignity, however well the client may treat the prostitute. Behind the humane treatment in the context of particular acts, one should always see the inhumane institution. In this sense, prostitution could be said to resemble slavery.

There is no denying the fact that prostitution as it exists nowadays is to a very large extent incompatible with respect for human dignity. Even before looking at the client who uses the prostitute for his sexual gratification, we must take account of all those people who use the prostitute as a source of revenue, keeping her under inhumane conditions, using violence against her whenever it pleases them, leaving her a very insubstantial part of what she receives from the clients, etc. Abducting a person, by force or by deceit, and then forcing her to prostitute herself is clearly contrary to human dignity and is rightly criminalized. And it can also be argued that clients who may be supposed to know that the prostitute is exploited can be criminalized.