Some Mormon women are obsessed with something illicit. They’re phoning friends, calling in favors and paying for international shipping to get it: a sacred tank top. The Church of Jesus Christ of Latter-day Saints has redesigned its temple garments, which are worn by faithful members under their clothes. The garments are effectively underwear that until recently, looked like white short-sleeve shirts and knee-length shorts. Now, the church has removed the sleeve on some designs, turning them into tank tops. The church is releasing the tops to its more than 17 million members around the world in phases. Last October, it...