If your firstborn is the only one with a baby book, that's not the only way your other kids are getting left behind. Firstborns have an intellectual advantage over their siblings, and birth-order parenting means your other kids are getting the shaft, according to a new study—even if you're not intending for it to happen.
The reason? Firstborns receive more mental stimulation from parents, while once other kids are born into the family, parents struggle to give the same time and attention to them.
In fact, as early as age one, kids who are not the firstborn already show signs of lagging behind their older siblings on cognitive assessments. The gap increases up until the time the younger siblings enter school, and still remains statistically significant from there on out.
The Journal of Human Resources published the results that draw from the National Longitudinal Survey of Youth (known as NLSY79, for short) which has followed more than 11,500 children born to women who were interviewed as part of NLSY79 and then later became mothers.
Once you've been through a pregnancy, the study showed, you're more likely to take more risks with subsequent pregnancies (for example, eating lunchmeat or sushi, despite those foods not being recommended by doctors for pregnant women due to the possibility of illness that can affect a fetus).
Moms having their second, third and fourth (or more) babies are statistically less likely to breastfeed, or to breastfeed as long as they did with their firstborn, as well.
And these differences in your parenting behavior can contribute to your child's educational outcomes as well as what kind of jobs they're able to get as adults.