This Is the Best Time to Have a Second Child, According to Science

The decision to have a second child is, in some ways, bigger than the first. From the added financial burden of baby number two to navigating a new social dynamic between siblings, welcoming another family member can be both exciting and nerve-racking. But an interesting new finding from the American Academy of Pediatrics may change the way you think about growing your family.

It turns out that children who have a sibling by the time they are in first grade are more likely to have a smaller waistline and lower BMI. Conversely, children in the first grade without a sibling were three times more likely to be overweight. To conduct the study, researchers recruited 697 kids from 10 different sites across the country at the time of birth. Every three months, they took body measurements of the children, also noting whether or not they had a new sibling. After grouping the children based on the timing of their brother or sister’s birth, they noticed a correlation between weight and siblings. Considering the pervasiveness of childhood obesity in American culture, these findings shouldn’t be taken lightly.

The researchers point to significant lifestyle differences as the reasons behind the large disparity. Most prominently, parents tend to focus less on the eating habits of the older child once a second one is brought into the mix, lowering the risk of overeating. Secondly, siblings serve as a built-in playmate, leading to more exercise and activity overall.

Would this influence your decision to have a second child? Share your opinion below, and shop this book on raising siblings to learn more.