Not the act, or even the movie about performing the act in the city, but the word "sex" from advertisements in Jerusalem and Petah Tikvah (which is where the Egyptian musicians were trying to go in The Band's Visit, remember?). Apparently the large religious population of both cities isn't comfortable with the word appearing on ubiquitous billboards, which puts the Israeli distributor of this summer's Sex and the City in a tough spot. Advertising that includes the film's title is out.
Now, it is kind of funny that while the movie can be shown anywhere, ads for it are banned in certain cities because they include the word "sex." But it might not be as petty as it seems at first glance. After all, people have to make an affirmative choice to go see the movie in a theater, or rent it on DVD; billboard and poster advertising is invasive and inevitably confronts unwilling audiences. It's not necessarily irrational to let theaters show the film but ban certain forms of promotion that everyone will see. This sort of thing isn't unprecedented in the United States: we permit sales of tobacco, for example, but ban television advertising and, in many communities, billboards near schools; we permit pornography, but not always graphic advertising for same. The ban on "sex" strikes me as the same sort of thing. You can still argue that a sensibility that is offended by any mention of the word "sex" is itself silly, but that's a can of worms.
[story in USA Today, via Movie City News]