A gene is a molecular unit of heredity of a living organism. In simpler terms, sections of DNA that contain complete instructions are known as genes. Since they are units of heredity, they can be passed on from one generation to the next. Genes determine which species a living organism belongs to (Arnqvist 1061). Genes usually encode for proteins. Proteins go out into the body and carry out the instructions given to them by the genes. Molecular engineering has been used to tinker with genes and to change what they code for. Sometimes these genes are removed entirely and replaced with different ones. In the long debate on homosexuality, many wonder if it is a lifestyle choice or if it is determined by one’s genes. Religious sects condemn it as evil and some even believe that prayers can ‘cure’ homosexuality. Scientists have carried out studies to try and find out if a gay gene exist and lay the debate to rest. In his article, Burr compares human sexual orientation to human handedness. Both traits have a majority orientation and a minority orientation. People do not choose to be left-handed and there is no gene that has been found for left-handedness (Burr para. 4). If there is a gene for left-handedness, it shows a lot of variation. Some left handed people use the left hand for writing while using the right for other activities while others use the left for particular activities only (Lalumière, Blanchard and Zucker 576). If this gene existed and it was similar to a gay gene, it would explain the difference in gay people. Some gay individuals’ exhibit highly feminine characters while others seem to be just on the edge between heterosexual and homosexual. Where then would one draw the line between being gay and being straight? Discovery of a gay gene would be a very important factor in eliminating doubt. If a gay gene is real, what would be the probability of inheriting it? In pedigree analysis, traits that are genetically influenced aggregate in families and in the case of dominant or sex-linked inheritance, are transmitted from one generation to the next (Dean 322). Since males receive the X chromosome from their mothers, if the X chromosomes contain a gene that increases the probability of being homosexual, then there would be a higher incidence of homosexuality in brothers. Human sexuality is complex and there is no single genetic locus that has been found to account for homosexuality (Dean et al. 323). Some scientists argue that it is not the presence of a gay gene but the absence of certain genes that causes homosexuality. There are certain proteins that control sex orientation in mice. A good example is an enzyme known as fucose mutarotase whose absence in mice was proven to cause an abnormal sexual receptivity. This is according to research carried out by Dongkyu et al (2). They were able to observe that mice lacking in the above enzyme could not utilize and incorporate fucose into protein. This led to masculine behavior and a preference for female urine. In a different study by Yan et al (para. 4), the neurotransmitter 5-hydroxytryptamine was discovered as being a requirement for male sexual preference. Previous studies have implicated this neurotransmitter in male sexual