Infertility means when a woman or a man cannot have a baby. A baby grows inside the mom's tummy and comes out after nine months. To make a baby, a mom and dad have to do something called "making love" or "having sex." During "making love," a dad's special liquid called "sperm" goes into the mom's tummy through a small tube called "vagina". One of the dad's sperms may meet the mom's egg inside the tummy and make a baby.
But sometimes, it's not that easy to have a baby. There are many reasons why someone may be infertile or cannot have a baby. For example, the mom's or dad's body might have something wrong with it or not be ready yet to have a baby. The mom might not have any eggs, or her eggs might not be healthy enough to make a baby. Also, the dad's sperm might not be swimming well, or there might not be enough sperm to meet the mom's egg.
Sometimes, the doctors can help the mom and dad to have a baby. They can give medicines or give the mom's body a little help to catch the dad's sperm. Other times, the mom or dad might need a special kind of surgery, or they might need to get help from a doctor who knows a lot about making babies.
So, infertility means having a hard time making a baby, but there are lots of ways to get help!