A karyotype test generally refers to a karyotype analysis, which is a common test used in the diagnosis of male infertility to check for chromosomal defects in men. The normal male karyotype is 46xy, meaning that it has 44 autosomes, one x sex chromosome and one y sex chromosome, and the resulting sperm will have a karyotype of 23x or 23y. If a man has a defective chromosome, it will result in the inability to form sperm or normal sperm, which will eventually lead to infertility.