Scientists have long known what your grandchildren-wanting parents and in-laws don’t want to tell you: Having children is hard on your marriage. Research since the 70’s has fairly consistently shown that, at least in the short-run, having children has a negative impact on marital functioning. Of course, this will surprise very few people who have had children, but just to sum up for any newlywed or single anticipating the joys of parenthood without a shred of grasp on reality: Babies are like black holes. The gravity of their needs warps and reshapes their surroundings. So, for the average new parent, baby means less time spent one-on-one with your spouse (or anyone else, for that matter), less energy or ability to do anything when you do have one-on-one time with your spouse, and a much greater likelihood that you and your spouse are going to be tired, grumpy and/or sick when you do spend time together, alone or otherwise. So, although life becomes qualitatively more rewarding once baby arrives, it is also very very likely to become quantitatively less fun.

There are of course exceptions to this rule. Social science describes groups much better than individuals. As the father of two exuberantly demanding 2½ year old twin boys, I will also admit something: If you are the exception to this rule, I hate you. However, scientists may now have discovered a more useful corollary to this rule that could either help you be the exception, or warn that you’re likely to suffer this fate so you can prepare accordingly: The amount of leisure time that you spend together with your spouse before baby arrives is directly (and positively) related to how happy you are likely to be in your marriage 1 year after baby is born.

Amy Claxton and Maureen Perry-Jenkins of the University of Massachusetts Amherst have reported in this month’s Journal of Marriage and Family that in a study of 147 couples examining marital functioning before and after the birth of a first child, relationships that reported higher levels of shared leisure time pre-baby were the more likely to report high levels of perceived love, and low levels of conflict 1 year after baby arrived.

Data were collected from 1996 to 2002 from 147 dual-earner couples (i.e., both husband and wife worked at least 35 hours a week outside of the home) experiencing the transition to parenthood for the first time. The current paper: “No Fun Anymore: Leisure and Marital Quality Across the Transition to Parenthood,” uses data from the third-trimester interview (Time 1), a 1-month postpartum interview (Time 2), an interview within 4 weeks of mothers return to work (Time 3), and a 1-year postpartum interview (Time 4). The paper reports that both husbands and wives report a decrease in shared leisure over the first year of parenthood (although it suggests that this may be temporary). More interesting, however, is the predictive relationship of shared leisure and non-shared leisure at Time 1 in predicting marital love and/or conflict at Time 4. For both wives and husbands, higher amounts of shared leisure with spouse at Time 1 predicted higher amounts of marital love at Time 4. However, shared leisure at Time 1 predicted less conflict reported by wives at Time 4, but not husbands, and higher amounts of leisure time spent with others at Time 1 predicted lower amounts of marital love at Time 4.

What’s the take-away here? Are men who spend more leisure time with their non-spouse friends more likely to resent the new demands of parenthood? Are they less likely to actually engage in their parental responsibilities within the home because they are there less once baby has arrived? It is unclear from this study how independent male leisure time is manifested. However, it would appear clear that couples are better able to weather the advent of parenthood, despite an almost universal decline in leisure time of any sort, if they are more engaged in shared leisure activities before baby arrives.

So, if you want to take out some “baby insurance,” take a look at how much time you and your spouse are spending together and just having fun. If you can count the number of times you’ve had fun doing something together in the past month on one hand: Institute a fun-time emergency! Make sure that you and yours are sharing in good times on a regular basis before you get pregnant. This may be one of the few cases where the treatment is as fun as the cure!