Guys: A word of advice. Marry pretty women or ugly ones. Short ones or tall ones. Blondes or brunettes. Just, whatever you do, don’t marry a woman with a career.

Why? Because if many social scientists are to be believed, you run a higher risk of having a rocky marriage. While everyone knows that marriage can be stressful, recent studies have found professional women are more likely to get divorced, more likely to cheat, less likely to have children, and, if they do have kids, they are more likely to be unhappy about it. A recent study in Social Forces, a research journal, found that women–even those with a “feminist” outlook–are happier when their husband is the primary breadwinner.

Not a happy conclusion, especially given that many men, particularly successful men, are attracted to women with similar goals and aspirations. And why not? After all, your typical career girl is well-educated, ambitious, informed and engaged. All seemingly good things, right? Sure…at least until you get married. Then, to put it bluntly, the more successful she is the more likely she is to grow dissatisfied with you. Sound familiar?

Many factors contribute to a stable marriage, including the marital status of your spouse’s parents (folks with divorced parents are significantly more likely to get divorced themselves), age at first marriage, race, religious beliefs and socio-economic status. And, of course, many working women are indeed happily and fruitfully married–it’s just that they are less likely to be so than non-working women. And that, statistically speaking, is the rub.

To be clear, we’re not talking about a high-school dropout minding a cash register. For our purposes, a “career girl” has a university-level (or higher) education, works more than 35 hours a week outside the home and makes more than $30,000 a year.

If a host of studies are to be believed, marrying these women is asking for trouble. If they quit their jobs and stay home with the kids, they will be unhappy ( Journal of Marriage and Family, 2003). They will be unhappy if they make more money than you do ( Social Forces, 2006). You will be unhappy if they make more money than you do ( Journal of Marriage and Family, 2001). You will be more likely to fall ill ( American Journal of Sociology). Even your house will be dirtier ( Institute for Social Research).

Why? Well, despite the fact that the link between work, women and divorce rates is complex and controversial, much of the reasoning is based on a lot of economic theory and a bit of common sense. In classic economics, a marriage is, at least in part, an exercise in labor specialization. Traditionally men have tended to do “market” or paid work outside the home and women have tended to do “non-market” or household work, including raising children. All of the work must get done by somebody, and this pairing, regardless of who is in the home and who is outside the home, accomplishes that goal. Nobel laureate Gary S. Becker argued that when the labor specialization in a marriage decreases–if, for example, both spouses have careers–the overall value of the marriage is lower for both partners because less of the total needed work is getting done, making life harder for both partners and divorce more likely. And, indeed, empirical studies have concluded just that.

In 2004, John H. Johnson examined data from the Survey of Income and Program Participation and concluded that gender has a significant influence on the relationship between work hours and increases in the probability of divorce. Women’s work hours consistently increase divorce, whereas increases in men’s work hours often have no statistical effect. “I also find that the incidence in divorce is far higher in couples where both spouses are working than in couples where only one spouse is employed,” Johnson says. A few other studies, which have focused on employment (as opposed to working hours) have concluded that working outside the home actually increases marital stability, at least when the marriage is a happy one. But even in these studies, wives’ employment does correlate positively to divorce rates, when the marriage is of “low marital quality.”

The other reason a career can hurt a marriage will be obvious to anyone who has seen their mate run off with a co-worker: When your spouse works outside the home, chances increase they’ll meet someone they like more than you. “The work environment provides a host of potential partners,” researcher Adrian J. Blow reported in the Journal of Marital and Family Therapy, “and individuals frequently find themselves spending a great deal of time with these individuals.”

There’s more: According to a wide-ranging review of the published literature, highly educated people are more likely to have had extra-marital sex (those with graduate degrees are 1.75 more likely to have cheated than those with high school diplomas.) Additionally, individuals who earn more than $30,000 a year are more likely to cheat.

And if the cheating leads to divorce, you’re really in trouble. Divorce has been positively correlated with higher rates of alcoholism, clinical depression and suicide. Other studies have associated divorce with increased rates of cancer, stroke, and sexually-transmitted disease. Plus divorce is financially devastating. According to one recent study on “Marriage and Divorce’s Impact on Wealth,” published in The Journal of Sociology, divorced people see their overall net worth drop an average of 77%.

So why not just stay single? Because, academically speaking, a solid marriage has a host of benefits beyond just individual “happiness.” There are broader social and health implications as well. According to a 2004 paper entitled “What Do Social Scientists Know About the Benefits of Marriage?” marriage is positively associated with “better outcomes for children under most circumstances,” higher earnings for adult men, and “being married and being in a satisfying marriage are positively associated with health and negatively associated with mortality.” In other words, a good marriage is associated with a higher income, a longer, healthier life and better-adjusted kids.

A word of caution, though: As with any social scientific study, it’s important not to confuse correlation with causation. In other words, just because married folks are healthier than single people, it doesn’t mean that marriage is causing the health gains. It could just be that healthier people are more likely to be married.

1. You are less likely to get married to her.

So say Lee A. Lillard and Linda J. Waite of the University of Michigan’s Michigan Retirement Research Center. In a paper, “Marriage, Divorce and the Work and Earnings Careers of Spouses”, published in April, 2000, they found that for white women, higher earnings, more hours of employment and higher wages while single all reduce the chances of marriage. “This suggests that (1) success in the labor market makes it harder for women to make a marital match, (2) women with relatively high wages and earnings search less intensively for a match, or (3) successful women have higher standards for an acceptable match than women who work less and earn less.” Some research suggests the opposite is true for black women.

Source: “Marriage, Divorce and the Work and Earnings Careers of Spouses,” Lee A. Lillard, Linda J. Waite, University of Michigan, Michigan Retirement Research Center, Working Papers, April, 2000.

2. If you do marry, you are more likely to get divorced.

In 2004, John H. Johnson examined data from the Survey of Income and Program Participation and concluded that gender has a significant influence on the relationship between work hours and increases in the probability of divorce. Women’s work hours consistently increase divorce, whereas increases in men’s work hours often have no statistical effect. “I also find that the incidence in divorce is far higher in couples where both spouses are working than in couples where only one spouse is employed,” Johnson said. A few other studies, which have focused on employment (as opposed to working hours) have concluded that working outside the home actually increases marital stability, at least when the marriage is a happy one. But even in these studies, wives’ employment does correlate positively to divorce rates, when the marriage is of “low marital quality.”

Sources: “A Treatise On The Family,” Gary S. Becker, Harvard University Press, 1981; “Do Long Work Hours Contribute To Divorce?” John H. Johnson, Topics in Economic Analysis and Policy, 2004; “Wives’ Employment and Spouses’ Marital Happiness,” Robert Schoen, Stacy J. Rogers, Paul R. Amato, Journal of Family Issues, April 2006.

3. She is more likely to cheat on you.

According to a wide-ranging review of the published literature, highly educated people are more likely to have had extra-marital sex (those with graduate degrees are 1.75 more likely to have cheated than those with high school diplomas.) One April, 2005 study, by Adrian J. Blow for the Journal of Marital and Family Therapy summed it up: “If a woman has more education than her partner, she is more likely to have a sexual relationship outside of her primary relationship; if her husband has more education, she is less likely to engage in infidelity.” Additionally individuals who earn more than $30,000 a year are more likely to cheat. “In a more general sense, it appears that employment has significantly influenced infidelity over the years,” Blow said. “The work environment provides a host of potential partners, and individuals frequently find themselves spending a great deal of time with these individuals.”

Source: “Infidelity in Committed Relationships II: A Substantive Review,” Adrian J. Blow, Journal of Marital and Family Therapy, April 2005.

4. You are much less likely to have kids.

According to the National Marriage Project, the incidence of childlessness is growing across the socioeconomic scale. In 2004, 20% of women over 40 remained childless. Thirty years ago that figure was 10%. But the problem–and it is a problem because the vast majority of women desire children–is much more extreme for career women. According to Sylvia Ann Hewlett, an economist and the author of Creating a Life: Professional Women and the Quest for Children, only 51% of ultra-achieving women (those earning more than $100,000 a year) have had children by age 40. Among comparable men, the figure was 81%. A third of less successful working women (earning either $55,000 or $65,000) were also childless at age 40.

Sources: The State of Our Unions 2006: Life Without Children, The National Marriage Project, July 2006. Creating a Life: Professional Women and the Quest for Children, Sylvia Ann Hewlett, Miramax Books, 2002.

5. If you do have kids, your wife is more likely to be unhappy.

A 2003 study published in the Journal of Marriage and Family concluded that wealthier couples with children suffer a drop in marital satisfaction three times as great as their less affluent peers. One of the study’s co-authors publicly speculated that the reason is that wealthier women are used to “a professional life, a fun, active, entertaining life.”

Sources: “Parenthood and Martial Satisfaction: A Meta-Analytic Review,” Jean M. Twenge, W. Keith Campbell, and Craig A. Foster, Journal of Marriage and Family, 2003; “Money doesn’t mean happy parenting,” USA Today, July 21, 2003.

6. Your house will be dirtier.

In 2005, two University of Michigan scientists concluded that if your wife has a job earning more than $15 an hour (roughly $30,000 a year), she will do 1.9 hours less housework a week. Of course, this can be solved if the husband picks up a broom.

Source: “Data Quality of Housework Hours in the Panel Study of Income Dynamics: Who Really Does The Dishes?”, Alexandra C. Achen and Frank P. Stafford, Institute for Social Research, University of Michigan, September 2005.

7. You’ll be unhappy if she makes more than you.

You aren’t going to like it if she makes more than you do: “Married men’s well-being is significantly lower when married women’s proportional contributions to the total family income are increased.”

Source: “Changes in Wives’ Income: Effects on Marital Happiness, Psychological Well-Being, and the Risk of Divorce,” Stacy J. Rogers, Danelle D. DeBoer, Journal of Marriage and Family, May 2001

8. She will be unhappy if she makes more than you.

According to the authors of a controversial 2006 study: “American wives, even wives who hold more feminist views about working women and the division of household tasks, are typically happier when their husband earns 68% or more of the household income.” Reason? “Husbands who are successful breadwinners probably give their wives the opportunity to make more choices about work and family–e.g., working part-time, staying home, or pursuing a meaningful but not particularly remunerative job.”

Sources: What’s Love Got To Do With It? W. Bradford Wilcox, Steven L. Nock, Social Forces, March, 2006; http://www.happiestwives.org.

9. You are more likely to fall ill.

A 2001 study found that having a wife who works less than 40 hours a week has no impact on your health, but having a wife who works more than 40 hours a week has “substantial, statistically significant, negative effects on changes in her husband’s health over that time span.” The author of another study summarizes that “wives working longer hours not do not have adequate time to monitor their husband’s health and healthy behavior, to manage their husband’s emotional well-being or buffer his workplace stress.”

Sources: “It’s About Time and Gender: Spousal Employment and Health,” Ross M. Stolzenberg, American Journal of Sociology, July, 2001; “Marriage, Divorce and the Work and Earnings Careers of Spouses,” Lee A. Lillard, Linda J. Waite, University of Michigan, Michigan Retirement Research Center, Working Papers, April, 2000.