A depressing article as a whole, but the section on infibulation was an especially horrific read.

There isn’t a reliable way to test for virginity as both the hymen and vaginal laxity vary with individual anatomy (most hymens partially cover the vagina and have one or more openings, but some women are born without any openings in the hymen or without a hymen altogether), the hymen can tear from non-sexual activity, the hymen may be flexible enough that penetration doesn’t result in tearing, and bleeding can be caused by injuries to vaginal walls rather than from damage to the hymen itself which has few blood vessels. [source]