Who would have thought that your mother or grandmother is all about sex?

A study recently released by the Kinsey Institute, a world authority on sexual behavior, indicated that between the ages of 40 and 70, men just want to cuddle and woman have sex on the brain.

Men were more likely to report being happy in their relationship, while woman women were more likely to report being satisfied with their sexual relationship, the report read.

And that's true of long-term couples all over the world.

The Institute studied some 1,000 couples, together for an average of 25 years, from the U.S., Brazil, Germany, Japan and Spain.

Although women are more interested in their sexual relationships than the actual relationships, it doesn't look like the typical American and Spanish woman is interested in many sexual partners.

More than 50 percent of U.S. couples remain in their first marriage, and that number goes up to 90 percent in Spain, said Julia Heiman, director of The Kinsey Institute, in the release revealing the findings.

Chilling to think that American grandmas are only in it for  the sex.