What is the ideal age gap between siblings?

In other words, when should you have another baby?

The spacing of children is a frequently debated topic and my patients ask me all the time what is best. One year? Two? Three? Four or more? My answer is always the same—there is no right answer. There is no formula for deciding when to have another baby; no one is going to tell you that one year, eight months or three years, two months is the perfect age gap. But there are indeed a number of things to consider when thinking about the ideal age gap between siblings.

Financial

It is expensive to have a baby and when considering adding to your family, you need to think carefully as to whether or not it is a wise financial decision for you right now. Infant daycare is more expensive than toddler, which is more expensive than preschool. So if you have two children close together, you might find yourself suddenly footing the bill for huge childcare expenses. There aren’t a lot of families who can easily cover that. However, if you have a nanny or a family member taking care of one child, it might not be a lot more expensive to add another. And in fact, it may be less expensive than extending your need to have child care by more years. But remember that if you have children close together in years, you might need to buy a second crib, high chair, car seat, stroller, etc.

Temperament of your first child(ren)

Parents who are lucky enough to have a really easy first child are often tempted to have another one right away. But be aware that a mellow six-month-old may turn into an extremely active 14-month-old. Conversely, a challenging first child might scare his or her parents into waiting a long time before risking another one. But a colicky baby may well turn into a charming toddler. As you weigh the pros and cons of adding to your family, you do need to take your child’s temperament into account, but don’t assume that personality is fixed. My younger daughter was one tough baby/toddler but suddenly at around four, she turned into miss sunshine and has been that way ever since. If she had been my first, I would have had to wait a long time before being brave enough to have a second!

Family pressure

I am always amazed at how intrusive people are in all sorts of ways; asking the question “so, when are you going to have another?” is shocking to me but new parents get it all the time. Whether or not to have another, and when to try to make that happen, are decisions totally up to you and your partner. And no one else. People tend to think they themselves did it right, so be prepared for those who had their children close together to encourage you to do so too. Don’t have another baby for someone else. Have another baby because that it what you and your partner want.

Age of parents/ease of conception

Something which is somewhat out of your control is your fertility. And as we age, we get less fertile. For women after age 35, fertility starts to decrease more rapidly. Men’s fertility declines with age as well, although less markedly. Depending on your age, you may not have the luxury of waiting years in between kids. This is especially true if you had trouble conceiving your first baby. However, it is not a science. I have had many patients who went through intensive infertility treatment to conceive their first, and then had a “whoops” when that baby was two months old. I have also had patients who conceived their first while using birth control, but then needed fertility treatment to have another.

Your own experience

One trap that parents often fall into is basing their decisions entirely on their own experience. Thus, someone who is close in age to a sibling who has a wonderful and close relationship with that sibling may well decide that having children close in age is the way to go, even if they might not be in a financial position or a life situation which is ideal to cover another child. I have several current patients who are frantic to have their children close together in age because of their own relationships with their siblings, even though having another baby right now does not seem like a wise decision to me. I have had other patients who chose to space their children far apart, because they did not have a good relationship with a sibling close in age, but then experienced infertility by the time they did start trying. Try to make the decision which feels right to your current family, not necessarily what happened in your family of origin.

Adding a child to your family should be a blessed decision. Make sure that you both feel comfortable with the timeline you have chosen.

By Alice Domar

Alice D. Domar, Ph.D is the author of the new book Finding Calm for the Expectant Mom (Tarcher, 2016). She is an associate professor of obstetrics, gynecology and reproductive biology, part-time, Harvard Medical School, the director of integrative care at Boston IVF, and the executive director of the Domar Centers for Mind/Body Health.