Their faces painted heavy with make-up, teenage girls in short, tight blouses and long petticoats loiter in squalid alleys, laughing and gesturing to potential clients who roam Tangail town's infamous red light area in the early evening. There is no shortage of men looking for "company" in Kandapara slum, a labyrinth of tiny lanes—lined cheek-by-jowl with corrugated iron shacks—a few hours drive northeast of Bangladesh's capital, Dhaka. But with rates as low as 50 taka (60 U.S. cents), the need to attract as many customers as possible is desperate - prompting a rising, yet dangerous, trend of steroid abuse among...