Forced sterilization is a very bad thing that can happen to some people, especially women. It means that someone is not given a choice and is made unable to have babies.
Think of it like a puzzle. Normally, when a mom and dad love each other and want to have a baby, a piece of the puzzle called an egg from the mom and a piece called sperm from the dad come together to make a baby.
But sometimes, sadly, some people are not allowed to have babies. They are made to have a medical procedure that makes their egg or sperm pieces disappear or not work anymore. This is called sterilization.
Sometimes, people who are not able to make good choices may be forced to do this. For example, it could happen if someone is in prison, or if they have a mental illness, or if they are poor, or if they have a disability.
This is really unfair because everyone should be able to make their own choice about having children. Nobody should be forced into losing their piece of the puzzle. Again, imagine if someone took away your favorite puzzle piece and you couldn't ever use it again!
It's important to remember that everyone deserves to have the same rights and choices in life, including the choice of if and when they want to have children.