Gender development can be explained by biological influences which includes hormones and genes. The base line of biological influences in gender development is that biological sex is determined by sex chromosomes, XX for female and XX for males. But this approach also argues that genes and hormones are the main influence on gender roles and gender identity in gender development.
A research by Riddle has found out that biological sex is determined by a single gene called CRY gene and argued that it also ultimately determines the gender roles and gender identity. When CRY gene is present and functioning normally then this will result in a ale otherwise in a female. CRY gene switches another gene called SOX which switches other genes that masculine the brain and the body by controlling the release of hormones including the most important hormone the androgen testosterone.
CRY gene determines both biological sex and gender in gender development, in rare cases where an XX male has a mutant non-functioning version of the CRY gene they will develop into normal fertile woman who develops female gender roles and female gender identity. In another study using genetic engineering, a female XX mice have been injected with an CRY gene into their embryo. It was mound that they have developed into males that demonstrated normal male sex role behaviors.
CRY genes researches provide valuable insights into how biology influences out gender development. It demonstrates how our gender is determined through the level of hormones that interact with our biological sex. Also the psychologists argue that CRY gene plays an important role in our gender development which includes gender identity and gender roles, therefore the biological approach can claim to have good face validity because it is testable and reasonable but also empirically supported explanation of gender development.
Although Riddle’s explanation of gender roles, gender identity and biological sex provides valuable insights into gender development an alternative explanation of gender development is Kohlrabi’s theory that claims that gender development is due to social and cognitive factors that are found have influence on gender roles and gender identity. However although Riddle’s explanation is considered not to be complete, unlike other explanations it has good scientific validity because the explanation is testable using genetic engineering, blood samples and genetic screening which suggests high internal validity.
One limitation of biological approach in gender development is that the research lacks population validity because its criticizes for anthropomorphism which means that the researcher used atypical sample of non-human animals with mutations on the CRY gene to carry out a research therefore the findings cannot be generalized to the role of biological influences on gender development in the wider population.
Also the biological approach can be criticizes for being genetically reductionism and deterministic because it only focuses on CRY gene and hormones in gender development therefore TTS far too simplistic because we cannot ignore the role of social and psychological hand, many psychologists argue that reductionism and/or determinism are needed to develop testable hypothesis when investigating complex behavior in gender roles. In fact scientific explanations are based on reductionism approach.
A research by Swab & Filers have found out that there’s a difference in female and male brains in the preceptor area of the human hypothalamus that is thought to determine our gender. A sexually dimorphic nucleus is bigger in males compared to females which suggests that out brain structure determines our gender development. The size of a sexually dimorphic nucleus results from a prenatal exposure to sex hormones which either feminism or masculine the brain.
This argument is thought to have good face validity because it’s a reasonable explanation of brain differences between females and males and its supported by a substantial research evidence that have demonstrated that hormones can influence gender role behavior, however it cannot conclude with certainty that hormones cause the brain differences due to individual differences.