Why do women have sex?

AUSTIN (KXAN) - Why do women have sex? It may seem like a simple question but according to the co-author of the new book, “Why Women Have Sex” it is rarely asked.

"No one has asked the simple question of why people have sex," said Dr. Cindy Meston, Clinical Psychology Professor at the University of Texas.

Meston explores the topic in great detail in her new book she co-authored with Dr. David Buss.

"If you want to improve sex you need to understand the underlying motivation," said Meston.

In order to determine why women have sex, three surveys were used.

First Meston surveyed 1000 women on why they have sex. Those reasons were broken down into 237 categories such as pleasure, loneliness, and boredom. Based on those categories another group of 1000 women were surveyed and asked, “How often do you have sex based on these reasons?”

For the book she used a qualitative method of in-depth interviews to ask women why they have sex. The book deals with first hand accounts of why and also why not women engage in sex.

"The main reasons were they were attracted to the person, they wanted the physical gratification, and they wanted the love and the commitment," said Meston. "There were just as many women as men saying they wanted sex because it was fun, it was exciting, it felt good, they wanted the pure physical gratification. And many said if a guy wanted a commitment it was viewed as negative."

One of the biggest misconceptions concerning sex is that women are engaging in sex as often as it’s seen on television. The average is actually much smaller.

"The average in the U.S. is four times a month," said Meston.

And while many women desire sex, not all want to have it.

"One third of women say they have a lack of interest in desire and this isn't just among older women this is among 20 year olds as well," said Meston.

Dr. Meston runs the University of Texas sex lab where she does much of her academic research.

"We have one of the few labs in the country that's capable of measuring the physical sexual response in women," said Meston.

Inside the lab a woman watches an adult video and has her heart rate, blood pressure, and sexual arousal measured.

"Women are hugely different in who they are attracted to, why they are attracted to them, what turns them on, how frequently they like to have sex," said Meston.

The goal of the book is to help women understand why they are having sex - whether it's for good or bad reasons.

"Consequently they will think more about it and be a better consumer of sex," said Meston. "They'll make better sexual choices for themselves and it really is an individual choice."