Really. Humans acquired pubic lice from gorillas several million years ago. We know what you're thinking, but that doesn't mean that humans and great apes were monkeying around.
A recent study shows that humans most likely got the gorilla's lice from sleeping in their nests or eating the giant apes. About 3.3 million years ago, lice found on gorillas began to infest humans. They took up residence in the pubic region largely because humans lost hair on the rest of their bodies and lacked of any other suitable niche.
Here's a head scratcher, though: humans are unique among primates as host to two different kinds of lice: one on the head and body (Pediculus), which has become the bane of many schoolchildren, and pubic or crab lice (Pthirus). In contrast, chimps have only head lice and gorillas only have pubic lice. Why that would be, and how the beasties distinguish the difference between a noggin and a crotch remains to be discovered.
Understanding the history of lice is important because the tiny insects give clues about the lifestyles of early hominids and evolution of modern humans. If you look at emerging infectious diseases that affect humans all over the world, most have their origins on some other host before threatening humans.
It is not unusual for lice to switch hosts, it occurs in both birds and mammals. Lice that lived on the passenger pigeon before it became extinct, for example, survive because they switched to another species of pigeon.
The host switch of pubic lice from gorillas to humans did not require sexual contact. Human pubic or 'crab' lice get transmitted between people on bath towels all the time. So it is easy to imagine that gorilla lice could have moved to humans via shared sleeping quarters, or predation.