d. It exists in a systematic form in
every civilization.

What is prostitution? There has been considerable discussion as to the
correct definition of prostitution.[121] The Roman Ulpian said that a
prostitute was one who openly abandons her body to a number of men without
choice, for money.[122] Not all modern definitions have been so
satisfactory. It is sometimes said a prostitute is a woman who gives
herself to numerous men. To be sound, however, a definition must be
applicable to both sexes alike and we should certainly hesitate to
describe a man who had sexual intercourse with many women as a prostitute.
The idea of venality, the intention to sell the favors of the body, is
essential to the conception of prostitution. Thus Guyot defines a
prostitute as "any person for whom sexual relationships are subordinated
to gain."[123] It is not, however, adequate to define a prostitute simply
as a woman who sells her body. That is done every day by women who become
wives in order to gain a home and a livelihood, yet, immoral as this
conduct may be from any high ethical standpoint, it would be inconvenient
and even misleading to call it prostitution.[124] It is better, therefore,
to define a prostitute as a woman who temporarily sells her sexual favors
to various persons. Thus, according to Wharton's _Law-lexicon_ a
prostitute is "a woman who indiscriminately consorts with men for hire";
Bonger states that "those women are prostitutes who sell their bodies for
the exercise of sexual acts and make of this a profession";[125] Richard
again states that "a prostitute is a woman who publicly gives herself to
the first comer in return for a pecuniary remuneration."[126] As, finally,
the prevalence of homosexuality has led to the existence of male
prostitutes, the definition must be put in a form irrespective of sex, and
we may, therefore, say that a prostitute is a person who makes it a
profession to gratify the lust of various persons of the opposite sex or
the same sex.

It is essential that the act of prostitution should be habitually
performed with "various persons." A woman who gains her living by
being mistress to a man, to whom she is faithful, is not a
prostitute, although she often becomes one afterwards, and may
have been one before. The exact point at which a woman begins to
be a prostitute is a question of considerable importance in
countries in which prostitutes are subject to registration.