WHY are there so many “ladyboys” in Thailand, and why are they such a huge part of the sex industry? Also, what’s up with the ping-pong-ball act? —Luke, an Ohioan in Bangkok

“PICK sexier topics,” Straight Dope staffers are always complaining. “Stop writing about the environment and give us something hashtaggable.” Well, here you go: a column on possibly the most notorious sex industry in the world.

But the joke’s on them, because half of this is going to be about Buddhism, and the other half about the foreign-economy-warping might of American military power. Still: sex, religion, and guns—what’s more compelling to the American demographic than that?

To start with the possibly obvious, the Thai sex trade is booming: it’s estimated there are some 200,000 prostitutes in the country, and the industry produces $2.5 billion to $4 billion each year, or around 1 percent of GDP. (A comparable percentage in the U.S. comes from “arts, entertainment, and recreation”—which I suppose might cover some of the same things.)

Kathoey—Thai slang for transgender women; the English term “ladyboy” is widely considered pretty offensive—are often the most visible part of the industry, even if the estimated rate of transgender people in the population is the same as in most other countries, roughly 0.3 percent.

Even outside the sex industry, transgender women in Thailand may be more socially integrated than their peers elsewhere in the world—in one study of 200 trans women there, the subjects were found on average to be better educated and more affluent than the country as a whole. And contrary to the suspicions of some, every participant in the study identified as female or transgender; none were men dressing up as women solely in order to attract tourist cash.

But, thanks in large part to the sex trade, Thai trans women have become a more visible part of the cultural landscape than their counterparts in the U.S. and most other countries. So what gives?

Much of it, it turns out, is probably Buddhism. The religion was adopted in Thailand by way of India about 800 years ago, and 95 percent of Thais now identify as Buddhist. Traditional Buddhists were never exactly sold on the whole sex idea in general. Reaching nirvana means achieving the absence of all desire, and sticking anything into pretty much any bodily orifice amounts to spiritual defeat for a monk, “even if only the width of a sesame seed” (not an optimistic bunch, these guys).

It wasn’t for lack of thinking about it: the Buddhist code of monastic conduct called the Vinaya lists 27 categories of people, creatures, and objects that one shouldn’t have sex with, including men, women, dead women whose flesh has or hasn’t been eaten away by animals, female monkeys, wooden dolls . . . you get the picture. Amid this overall disdain for getting off, heterosexual sex and homosexual sex were viewed as (at least for monks) equally sinful.

Transsexualism is also surprisingly well-defined in Buddhist scripture, and is described in great detail in several stories. The historian Peter Jackson has argued that pre-existing Thai notions of gender interacted with Buddhist thought in a way that uniquely conflated gayness with transness; for many years gay men were simply understood as having women’s desires, and often referred to as kathoey too. But while same-sex inclinations were long thought in Thai Buddhism to be sinful, they were also thought to be congenital—meaning they couldn’t be changed during a person’s lifetime, and therefore had to be accepted.

Of course, this doesn’t exactly constitute a Caitlyn-Jenner-on-the-cover-of-Vanity Fair level of public acceptance—no one’s claiming Thailand is a perfect role model for the equal-rights movement. But compared to Christianity’s effects in the West, Buddhism has helped create a society that’s probably more accepting of divergence from traditional orientation and gender norms; Jackson describes Thai gay and trans subcultures that are notably vibrant, if idiosyncratic.

The sex-industry part of the story is much simpler. When American troops fought in the Vietnam War, roughly 700,000 of them passed at some point through Thailand, the U.S. military’s official rest-and-relaxation area. Their spending in restaurants, bars, and brothels exceeded 40 percent of Thailand’s export earnings, all happily paid for by the American government, and produced a proliferation of sex-based businesses. See also: the Philippines while the U.S. had bases there, and Korea during the Korean War and since.

To complete the equation, transgender populations all over the world are much more heavily involved in prostitution than the population at large, because thus far no society is so accepting of transness that it’s simple for a publicly transgender person to find other employment.

Here in the U.S., the National Trans Discrimination Survey reported in 2011 that 26 percent of transgender people had lost their jobs due to gender identity/expression and 11 percent had done sex work for income. With Thailand’s high-profile sex trade, these trends stand out all the more.

As for that ping-pong-ball trick, let’s just say the physics behind it is pretty simple. The rest I’ll leave to your imagination and/or your Google search history.

This article appears in Jul 29 – Aug 4, 2015.