New evidence from famed happiness researcher Richard Easterlin shows that women are happier than men in early adulthood, but at age 41, this switches, and men are happier later in life. Easterlin says this gap comes from frustration over an inability to get married. Because most people want to be married, and if you want to be married but you can't get married, you are unhappy.

Intuitively it makes sense that younger women marry more easily than younger men— young women are hot, and they are out-earning their male counterparts, while young men are suffering a masculinity crisis. However as everyone ages, the men earn more money and the women have flabby thighs.

But I don't think the issue is, as Easterlin says, marriage. I think the real issue is children. Having kids complicates a woman's life in ways that are not so difficult for men. It's true that men today are more involved in parenting than ever before, but still, children affect women so much that they don't start earning less than men until they have kids.

Here's the deal with parenting: men believe they are doing a great job of parenting no matter what they're doing, and women always think they could do better. So a woman does better in marriage and career early-on, but when she adds kids to the mix, her self-esteem is challenged (second-guessing her parenting) and her ability to support herself is challenged (she earns less money) and she becomes increasingly dissatisfied.

I'm sure a bunch of women will write to tell me that their kids are the love of their life. But don't bother. Because I'm not saying women don't love their kids, and maybe I am saying that the lack of happiness is precisely because women love their kids so much.

So here are three things to do if you're a woman who wants to hedge against unhappiness in later life.

1. Don't have kids. Daniel Gilbert (who has a son) has great research to show that kids do not make people happier. Kids give great joy but also wreak great havoc. People used to think there is something wrong with women who don't want kids. But really, there is something wrong with people who tell you that their kids make them happier: they are lying. Of course, it might not be intentional. And anyway, we lie to ourselves about a lot of things that we can't change. But stop thinking that everyone should have children. Maybe not.

2. Keep your career. In her book, Necessary Dreams, Anna Fels reports that women struggle to have careers when their children are young. But when the kids are older, the women who kept their careers throughout the early years of raising children are much happier than the women who gave up careers. This research does not, of course, take into account who was happy when they were going on a three-day business trip and leaving a one-year-old at home with the nanny. Also, keep in mind that quitting work to have kids and reentering the workforce later is not that difficult for moms today. So get back into the workforce as soon as you think your kids can handle it; the benefits will ripple throughout your life.

3. If you are divorced, get plastic surgery. I am convinced that a lot of the reason women are happier earlier in life is that women have more control over their destiny when they are better looking. We know that people who are better looking get treated better throughout life, and we know that younger women do better remarrying than older women. So women should get plastic surgery if they get divorced so that they can remarry faster.

I say this about divorced women, but to be honest, I'm not taking the advice. It rings true to me, but it's hard advice to swallow. The incurable optimist in me tells me I'll do fine getting remarried just by being me.

But then, that's the trouble with all research—when it suggests a change you weren't already excited about, you decide that it doesn't apply to you. And I'm no exception.