Why does down syndrome occur in both boys and girls?

Down syndrome, caused by the presence of extra copies of chromosome 21, occurs in both boys and girls due to the random nature of chromosomal abnormalities. It is not related to gender.

During meiosis, the process of forming reproductive cells (eggs and sperm), chromosomal errors can occur, leading to an uneven distribution of chromosomes. This can result in the formation of gametes (egg or sperm) with an extra chromosome.

If an egg or sperm with an extra copy of chromosome 21 participates in fertilization, the resulting embryo will have an extra copy of this chromosome, resulting in Down syndrome.

The chance of having a child with Down syndrome is influenced by various factors, such as advanced maternal age, genetic predispositions, and certain medical conditions, but it is not specific to a particular gender. Both boys and girls are equally at risk of being born with Down syndrome.