With an extra chromosome, can people with Down syndrome have babies? Will those babies also have an extra chromosome?
Great question! In the past, it was believed that males with Down syndrome were unable to have babies. Basically they believed them to be infertile. But let's be realistic, people with Down syndrome have only been "allowed" to date an marry as of recently. I say "allowed" because somehow we took away their right to love and be loved in claims that their intellectual IQ made them unfit to marry, yet, what they know to do best is love.
Now a days, individuals with Down syndrome are dating and getting married. Some of them are even having babies. However, the choice of having babies continues to be controversial, and a hard choice to make, as it usually involves family beyond the couple. Many couples choose not to become parents because they are unsure they are able to parent a child without help.
But the questions is, can they have babies? And will their babies have Down syndrome too?
In order to understand what happens when sperm and egg of people with Down syndrome unite, we need to look at the basics of cell reproduction.
There are two ways in which cells reproduce: meiosis and mitosis.
Mitosis: This is how all cells (except sperm and egg) reproduce themselves.
"A process of asexual reproduction in which the cell divides in two producing a replica, with an equal number of chromosomes in haploid cell."
Meiosis: This is how sperm and cell reproduce.
"A type of cellular reproduction in which the number of chromosomes are reduced by half through the separation of homologous chromosomes in a diploid cell."
We all have 46 chromosomes, therefore, egg and sperm have 23 chromosomes each. When they unite, you get 46 all together (23+23=46)
People with Down syndrome have 47 chromosomes (an extra 21st). Now picture the 47 chromosomes reduced, or divided in half. You get one "half" with 23 chromosomes (or a typical cell) and one with 24 (with the extra 21st chromosome)
The grid bellow, shows you what the chances are for two people with Down syndrome to have babies (assuming that both individuals are fertile and able to procreate).
As you can see, for 2 people with Down syndrome having babies, the chances are as follows:
-25% chance their child will be typical (no Down syndrome)
-50% chance their baby will have Down syndrome
-25% chance there will be no viable pregnancy
Although Down syndrome awareness month is done, if you have any more questions...ask away!