During these processes, the newly generated sex cell has only half of the genetic information compared to a somatic cell. A somatic cell has 46 chromosomes (23 kinds, one of each kind from each parent). A sex cell has only 23 chromosomes - either mom's or dad's for each type of chromosome.
New genetic combinations arise in small amounts because of crossing over. During meiosis, chromosomes may exchange a small segment of one of their arms, creating a new combination of genes.
The most significant way that new genetic combinations arise is when an egg and sperm unite. Now, half of one person's chromosome set is joined with half of another person's, creating a full set of chromosomes that is different from each parent.