Men are built to have a lustful, wandering eye but women should not worry that their partners will stray like Tiger Woods.

So says the author of the new book "The Male Brain," psychiatrist Louann Brizendine, known for her bestseller "The Female Brain."

"The way Mother Nature made us, the man's job on the planet is to look for, search for and seek out fertile females to mate with," she told Reuters in an interview.

The biggest misunderstanding women have about men is their complaints about men peeking at a woman's figure or watching an attractive woman walk by, Brizendine said.

"She doesn't understand that this is how he is wired," she said. "It's not that he doesn't love you."

Just because men ogle women, she said, it does not mean they will have extramarital dalliances like top golfer Tiger Woods or Jesse James, the husband of actress Sandra Bullock.

"There is the normal range of behavior and then there is pathological behavior," Brizendine said.

"Clearly Tiger crossed over the line," she said. "A few men like that give all men a bad name."

The best indicator to whether a man will be faithful is whether his father was faithful, as genes that cause monogamy are passed from father to son, according to "The Male Brain."

That Will Be a Short Book

After making a name for herself as an expert on gender differences with "The Female Brain" in 2006, Brizendine said she wanted to write a bookend to that in hopes it will help couples having trouble talking or understanding each other.

She says in the book's introduction that when she told friends of her plans to write about the male brain, almost everyone replied "That will be a short book!"

Indeed, the book is shorter than her previous one. While "The Female Brain" was 180 pages excluding notes and references, "The Male Brain" is a more concise 135 pages.

Still, the book reveals men's minds to be every bit as complex as women's, as evidenced by the 124 pages of notes and references.

The cover shows a brain made from duct tape -- an homage to her claim that men are problem solvers.

"The male brain is more of a fix-it brain," Brizendine said.

When a woman tells a man something has upset her, he is likely to tell her what she should do, she said.

Instead he should say "Honey, I know how you feel," Brizendine said. "She wants that resonance of emotional empathy."

But rather than get annoyed, women should learn the typical response is men's way of expressing love and care, she said.

Even men like Brizendine's husband, a renowned neuroscientist, fall down in the empathy department but she has trained him well.

"I put on my husband's computer a little yellow sticky that says 'Honey, I know how you feel,'" she said. "He says the words out loud and even though we know the words are scripted, we laugh and it does feels better."

Brizendine says she wrote both books to help patients -- she runs the Women's Mood and Hormone Clinic in San Francisco and teaches at the University of California at San Francisco -- and she has been surprised by their commercial success.

With both sides of the gender divide now covered, she said she has no ideas yet for another book.

Her writing has led to unusual offers that she has rejected -- working as a marketing consultant on selling to women, hosting a television show giving advice and endorsing women's products from clothing to soap.

Brizendine is not sure what endorsement offers will emerge after her latest book.

"Let's hope it's not Viagra," she said.