SAN FRANCISCO – Spending beyond your means. Accepting a low salary to avoid being seen as greedy. Lying to friends or a spouse about the cost of your purchases.

Both sexes can fall victim to irrational money behavior, but these are some of the ways women especially undermine the financial security they’re seeking, financial experts said.

Women may not realize it, but their reluctance to face up to their conflicted feelings about money may cost them dearly, said Liz Perle, author of the book “Money: A Memoir.” After recounting some of her own financial mistakes, Perle spoke with more than 200 women about their money habits and found similar complexities emerged.

“No one wants to admit they shave a couple bucks off the price of a lipstick when they’re telling a friend or say ‘I got it on sale’ when it never was.”

“We’re kind of embarrassed by our appetites,” Perle said. “It leaves us in this highly ambivalent relationship with money.”

Separating material desires and emotional needs from the business of making a living proves difficult for many, she said. “Money and love are very commingled for women, and money, and fear and money, and scarcity – the bag-lady fear.”

“They might have some feelings they don’t think are right to have, like the fact there is still this sort of Prince Charming fantasy. It doesn’t have to be a man anymore. It could be a parent’s going to bail you out or a job’s going to bail you out, or a lottery ticket or the novel in your drawer.”

The sexes have become more alike in their money lives in the last generation as women joined the work force en masse. But some of women’s behaviors, such as a general female aversion to negotiations, may be holding them back.

Nowhere is such self-denial more crucial than with the salary negotiations for a first job, when women may feel the least confident asking for what they think they’re worth.

Working women earned 80 percent of men’s median weekly earnings in 2005, up from nearly 63 percent in 1979, according to the Bureau of Labor Statistics.

In what could explain some of the chronic wage gap, men are more than four times as likely to negotiate a first salary, said Linda Babcock, co-author with Sara Laschever of the 2003 book “Women Don’t Ask: Negotiation and the Gender Divide.” What’s left on the table over the long term can be staggering: The consequences of failing to negotiate a first salary can lead a person to lose more than $500,000 by age 60, Babcock said.

“We’re not really responding to market conditions when we decide to negotiate or not,” she said. “We’re responding to how we’ve been socialized as girls.”

Much of the preparation to make sound financial and employment decisions begins in childhood. Still, fewer girls than boys are getting the message to see themselves as enterprising providers, Perle said.

That has to change, she argued, so girls aren’t told they’re just good with children for babysitting while boys are told they’re entrepreneurial for moving lawns.

As more women graduate from college than men, the prospect of having more women with higher earnings requires both sexes to brush up on their communication and conflict-resolution skills, Perle said.

“Right now we’re caught in this wacky gap for women where we’re working in our fathers’ worlds and still holding ourselves up to the mythic 50s mother standard,” she said. “Women have to realize all these forces are at play with their pocketbooks.”