The title says it all. Here in the United States, especially the south, I've heard growing up never to hold a frog because it will pee on you and the pee causes warts.
This urban legend has been debunked so often and so consistently on the Internet, it is almost redundant to repeat it.
Here are just some of the sources - including many medical experts and frog experts.
"Warts are caused by a human virus, not frogs or toads," says dermatologist Jerry Litt. But the wartlike bumps behind a toad's ears can be dangerous. These parotoid glands contain a nasty poison that irritates the mouths of some predators and often the skin of humans. So toads may not cause warts, but they can cause other nasties. It's best not to handle these critters—warts and all!
Dr Lee Grismer is a herpetologist from La Sierra University in Los Angeles in the United States.
According to Dr Grismer, the warts on toads are an accumulation of mucus glands and poison glands that are in the skin.
"When the toad is alarmed or feels threatened it can actually produce a milky secretion that comes out of those glands," he says.
The toad we're most familiar with in Australia is the cane toad. Handle it roughly, and it's likely to react by excreting a bufo toxin — ingest this toxin and you'll set off a chain reaction which could include intense pain, seizures, cardiac collapse, even death. But there's one thing these fellas won't give you, and that's warts.
- Whit Gibbons, Herpetologist
An old superstition has been that toads can give you warts (they do indeed have wart-like bumps on their bodies), but I have never seen any scientific evidence that it is true for toads or frogs. Until someone actually proves that it can happen (and no one ever has), let's assume it is not true. As far as a frog actually carrying a virus that causes warts, my dermatologist says she has never heard of that being a problem.
- Jeff Beson M.D., Bowden Orient
Humans are the only known reservoir of HPV. No other animals, including toads, are known to carry or transmit the virus
WARTS are NOT caused by touching a toad or frog!