A new German study says that porn may had adverse effects on your brain.

Researchers from Max Planck Institute for Human Development in Berlin said that men who watch a lot of porn usually have smaller striatum, which is the area of the brain that is "linked to rewards and motivation," said Telegraph.

The connection between the striatum and the prefrontal cortex also decreases when watching increased amounts of porn. The prefrontal cortex is responsible for behavior and decision making.

Although it is believed that porn causes the brain to shrink, there is also another possible reason. Perhaps those with smaller brains are more attracted to porn.

On top of a possible shrinking brain, a lot of porn also makes it difficult for people to become aroused by sexual partners in real life, there are potency problems and some become bored by mainstream porn and start looking for more extreme substitutes.

A survey by the University of East London said that 97 percent of boys between the ages of 16 and 20 have viewed porn. For girls of the same age, the number is 80 percent. One in three women regularly watches pornography, and 70 percent of men that are 18 to 24 visit porn sites at least once a month.

A study in Canada by MediaSmarts showed that boys in Canada are regularly looking for porn, which is troubling for a group that is still learning what sex is.

"There's a significant number of students, and boys obviously in particular, for whom it is a really frequent behavior," said Matthew Johnson, director of education for MediaSmarts. "They're still developing their sexuality, they're developing their ideas of what is normal in sex, they're developing a sexual identity and they're developing an idea of what is appropriate in relationships. So obviously heavy exposure to pornography can be problematic in all of these areas."