Jennifer, A parent has two of each chromosome – they “recombine” these into two new chromosomes and one is passed to the child. The recombination process usually involves one to three crossovers (resulting in two to four large segments), but sometimes there are no crossovers (resulting in one of the two chromosomes being passed down intact), or four or five crossovers (resulting in more, but smaller segments). On average, we should expect one or two of the chromosomes to be passed along intact in each generation. Usually it will be different for each child, but it doesn’t have to be.