INTRODUCTION Caenorhabditis elegans are nematodes that feed on Escherichia coli. and live on vacant land. C. elegans makes a good model organism because it is small, short-lived, reproduces rapidly and has many descendants, is easily and cheaply grown in the laboratory, there is visible phenotypic differentiation between the different genotypes and there is a lot of knowledge on their genome. C. elegans have most major differentiated tissue types which include; nerve, muscle, hypodermis, intestine and gonad. C. elegans is also useful because it can be stored in liquid nitrogen and is still viable.C. elegans have two genders, hermaphroditic and male. The hermaphrodite has two X chromosomes. It is self-fertilizing, meaning it can produce offspring without needing another C. elegans. This is supported by Current Topics in Developmental Biology when describing genotype (Ross Wolff & Zarkower, 2008). When C. elegans hermaphrodites are young they produce and store sperm. When C. elegans is older, it produces eggs. According to the Merriam-Webster Dictionary website, an oocyte is an egg before it matures (Merriam-Webster). The ovules are fertilized by the sperm and complete part of their development within the hermaphrodite parent.C. elegans males are rarely produced in a hermaphroditic population by meiotic nondisjunction with a frequency of 0.1%. Nondisjunction is, according to the Genetics Home Reference, when chromosomes or chromatids fail to separate properly. (Genetics Home Reference). Males have only one X chromosome. This is supported in the Developmental Biology Journal when it states that hermaphrodites are XX and males are org/. Web. 28 February 2014. .Morgan, Dyan E., Sarah L. Crittenden, and Judith Kimble "The adult male C. elegans germ line: stem cells and sexual dimorphism 346.2 (2010): 204-14." Web. 28 February 2014. “Nondisjunction.” Genetics Home Reference, 25 February 2014. Web. 28 February 2014. “Oocytes.” 2014. Ross Wolff, Jennifer and David Zarkower “Somatic sexual differentiation in Caenorhabditis Elegans.”".. 2014. .