However, the case of pseudo-hermaphrodites may refute the theory of biological factors on gender development. True hermaphrodites are born with both male and female genitalia and are therefore both sexes to some extent. Pseudo-hermaphrodites are chromosomally one sex but appear physically as the opposite sex. This means that there must have been the wrong hormones must have been stimulated in order for different sex organs to be produced.
Also, there is evidence that shows that that there is more than just biological influences on gender. Daphne Went, for example is chromosomally male but has female genitalia (androgen insensitivity syndrome) and was raised as a female. Despite having a Y chromosome, she lives successfully as a female. This evidence refutes the argument that only biology has an influence on gender, as if a person has a Y chromosome they should develop male sex organs, be exposed to male sex hormones, and develop male brain lateralisation.
However, the cases can also support the argument that biology has an influence on gender, as in the cases with androgen insensitivity syndromes and androgenital syndrome, as it shows that hormones can determine gender and not just genes. It shows that gender can be determined in the pre-natal environment.
Pfeiffer (1936) investigated whether there were differences in the brains of male and females. He removed the sex organs of genetic males and female newborn rats and found that they developed into adults with female hormone release patterns from the pituitary glands . When some of the rats (male and female) had testes transplanted onto them, there was a steady release of male sex hormones from the pituitary gland. This suggests that the differences in the hypothalamus depend on whether testosterone is present. If testosterone is present, the hypothalamus will tell the pituitary gland to release male hormones, and the absence of testosterone will result in the hypothalamus telling the pituitary gland to release female hormones. However, there is evidence that refuses this, for example, Dorner (1976) found that damaging a small part of the hypothalamus of newborn male rats resulted in them showing female behaviour as they grew up, therefore suggesting that there was disruption to the normal release of male sex hormones.
However, Pfeiffer also found that that female have a smaller sexual-dimorphic nucleus (SDN) than males. Studies have also proved that the SDN plays a role in sexual partner preference; it suggests that those that have an average sized male SDN will prefer females and also that they will show stereotypical male behaviour.
Furthermore, Swhwaab investigated the brains of transsexuals and found that the chromosomally male transsexuals had the SDN size of that of an average female. Thus supporting the argument that gender is determined before birth.
There has also been some evidence of show that in males, the left hemisphere of the brain is more active than the right during linguistic tasks, but in females there is more likely to be bilateral activity in the brain during the same tasks. Therefore, it is more likely that damage in the hemisphere will affect males more than females will.
There is an argument forwarded by Dr.Money who stated that nurture can override nature. Gender development depends on observational learning and reinforcement in developing roles. For example, girls are given baby dolls to play with to reinforce their ‘maternal’ role while boys are given cars etc. Children would often be praised for displaying the right behaviour in their gender role and might carry on doing so in order to please their parents (e.g if a boy was to pick up a Barbie dolls instead of a car, it might be taken away but if he helps his dad wash his car to mend the leaking sink, the behaviour might be praised, therefore leading the child to behave the way they are expected to behave). Even though, Dr.Money published that his case study of David (Brenda) Reimer was successfully living as a girl, despite being born a boy, this was not true. David was raised as a girl from the age of 22 months, was surgically converted into a girl and encouraged to fulfil female roles (e.g dresses, playing with dolls) but he however, felt that he was boy and would often play with masculine toys and would even urinate standing up. By the age of 14, the decision was made to allow him to live as a boy. Therefore, Dr.Money’s case study has actually supported the counter-argument that biological gender is more determinate of the child’s gender identity.