Economists claim to study markets in all their forms.
But one, in particular, seems to make them blush: sex work.
In a new book, "Sex Work by Numbers", Stef Adriaenssens of KU Leuven, a university in Belgium, estimates
that less than 5% of the 18,232 academic publications
on the industry produced between 2000 and 2024 took an economic or business view.
By comparison, 40% concerned biology or medicine, more than 25% related
to psychology or psychiatry and almost 20% had to do with the law.
A quick search for "sex work" or "prostitution" in the database of the National Bureau of Economic Research,
a collection of working papers, generates just 178 results among 35,450 articles.
That is a big omission for what is a large industry.
Porn alone is thought to generate almost $100bn in revenues a year worldwide, twice as much as AI.
OnlyFans, a subscription site known for X-rated content, hosts 4.6m creators, many of them in adult entertainment.
It has 380m users who together spend over $7bn a year.
Estimates from UNAIDS, a UN agency, put the share of the world's women aged 15 and over engaged
in "exchange of sexual services" at 0.6%.
In sub-Saharan Africa, this rises to 1.3%.
Sex work is, granted, difficult to study.
It covers all manner of X-rated activities.
A streetwalker in Nairobi, a high-end escort in London and a cam-girl in Kyiv inhabit utterly different economic worlds.
Many switch between pornography, stripping and prostitution as demand requires.