Although we are all unique, there are often obvious similarities within families. Maybe you have the same nose as your brother or red hair like your mother? Family similarities occur because we inherit traits from our parents (in the form of the genes that contribute to the traits).
This passing of genes from one generation to the next is called heredity. Simple organisms pass on genes by duplicating their genetic information and then splitting to form an identical organism. More complex organisms, including humans, produce specialised sex cells (gametes) that carry half of the genetic information, then combine these to form new organisms. The process that produces gametes is called meiosis.
Through stages of meiosis and mitosis (cell division), DNA is split and transferred to the child. The new offspring inherits exactly half the DNA from each of their parents, while each parent passes half their DNA to each of their children. During sexual fertilization, DNA from both the parents combine.
