AAB Molecular Diagnostics Practice Test 2026 – Complete Exam Prep

In human cells, there is a total of 23 pairs of chromosomes. Out of these, 22 pairs are known as autosomes, which are chromosomes that do not determine sex. The remaining pair consists of the sex chromosomes: two X chromosomes in females (XX) or one X and one Y chromosome in males (XY). Therefore, when looking specifically at the sex chromosomes, there is indeed only one pair present. This makes the understanding of how sex is determined in humans clear, as the combination of these sex chromosomes is what differentiates male from female.