G-banded Karyotype of a male patient with an extra chromosome 13, a condition known as trisomy 13, or Patau syndrome. A karyotype is a photomicrograph of chromosomes that looks at the number, form, and size of the chromosomes of an individual or species. This karyotype characterizes a human male as it contains both the X and Y sex chromosomes. Two X chromosomes would determine a a female. Human beings have 23 Chromosomes and normally there are two copies of each chromosome in each of our cells, one set from the maternal and the other from the paternal parent. As noted earlier, there is an extra chromosome 13 in this Karyotype, this is due to a nondisjunction of chromosomes during meiosis.