Human DNA is packed into roughly X-shaped structures called chromosomes. Each cell in your body has a copy of your DNA in 23 pairs of chromosomes. You inherit one of each pair from your mother and the other from your father.
One pair are the sex chromosomes, called X and Y. Females usually have two X chromosomes and males usually have an X and a Y chromosome.
|Other species have a different number of chromosomes to humans - butterflies have around 380 pairs.|