The Biology of Reproduction

Every organism must reproduce (create offspring) in order to pass a part of themselves on into future generations. Depending on the organism, it can either reproduce using sexual or asexual reproduction, which both involve cell division. The parental traits of sexually reproducing organisms will also mix to form a unique combination in the offspring, and…

Sperm

Sperm are the male reproductive cells found in semen. When mature and motile, they are referred to as spermatozoa (singular: spermatozoon). In humans, sperm cells ideally contain 23 chromosomes (half of a human’s genetic material) and may combine with the 23 chromosomes contained in a female’s ovum during fertilization to form a new human being.1 A…

Sex Determination and Differentiation

In humans, biological sex is determined by a specific set of chromosomes. Chromosomes are long, threadlike structures of DNA that encode for different traits in an organism. Humans have a total of 46 chromosomes. These include 22 pairs of autosomes, which are the chromosomes that are the same in males and females, and one pair…