Can You Have a Baby With Down Syndrome If You Are Under 35?

Yes, you absolutely can have a baby with Down syndrome if you are under 35. In fact, despite the strong association between advanced maternal age and the condition, the majority of babies with Down syndrome are born to mothers who are younger than 35 ^[1]. If you are a younger mother who has just received a diagnosis for your child, it is completely normal to feel shocked, confused, or isolated, but you are not alone.

Why Does This Happen?

There is a widespread cultural misconception that only older women have babies with Down syndrome. This misunderstanding comes from how we talk about statistical risk. It is true that as a woman gets older—especially past age 35—her individual chance of having a baby with Down syndrome increases ^[2][3].

However, younger women have a much higher birth rate overall. Because women in their 20s and early 30s account for the vast majority of all pregnancies and live births, they also account for the majority of babies born with Down syndrome ^[4][5].

How Does Down Syndrome Occur?

Down syndrome is caused by an error in cell division that results in an extra full or partial copy of chromosome 21. This happens at conception and is not caused by anything you did or did not do before or during your pregnancy. It is not tied to your lifestyle, diet, or activities.

There are three main types of Down syndrome:

• Nondisjunction Trisomy 21: This accounts for about 95% of cases, where every cell has three copies of chromosome 21 instead of two. It is caused by a random error in cell division.
• Translocation: This accounts for about 4% of cases. An extra part or a whole extra chromosome 21 is attached to a different chromosome. Unlike nondisjunction, this type can sometimes be inherited from a parent who is a genetic carrier.
• Mosaicism: This is the rarest form (about 1%), where only some cells have the extra chromosome.

While maternal age is the most established primary risk factor ^[2][3], the genetic changes that lead to Down syndrome occur spontaneously in the vast majority of cases.

Moving Forward

A diagnosis can feel overwhelming, especially when it challenges what you thought you knew about Down syndrome and age. The most important thing to know is that this is not your fault.

Since your baby’s diagnosis might bring up questions about your risks in future pregnancies, it is very helpful to speak with a genetic counselor. They can look at your baby’s specific type of Down syndrome (such as translocation) and explain what that means for your family planning.

Connecting with organizations like the National Down Syndrome Society (NDSS) or local early intervention programs can also give you actionable next steps and help you find a community of parents—many of whom are also younger mothers—navigating this same journey.