Gender Testing in Sports
Part III - Human Embryology
The How and Why of Genetic Mutation that leads to Ambiguous Gender
My previous post had described the changes that take place in the embryo at seven weeks after conception and this post is a continuation of it.
Until seven weeks after fertilization, the embryo is neither a male nor a female; it is considered
“bipotential” because the gonads have not become testes or ovaries. The embryo waits for signals from its DNA to start it on its path to become a male. If no signal is received the embryo becomes a female and if a signal is received from the Y chromosome, a male will be formed. A
gene known as SRY found on the Y chromosome turns the bipotential gonads into testes. The testes produce specific male hormones that influence the completion of the male gender. The SRY gene could have a mutation that makes it inoperative, or it may be deleted, but the process of male development cannot occur without a functional SRY gene.
The SRY gene sets off a series of events that take place in the embryo and continues through adolescence of the child.
This cascade depends on activation of many different genes and proteins for completion and this multi-step process of sexual development can be interrupted at many places along the way resulting in ambiguity of gender of the affected person. These genes are just as important as the SRY gene and hence testing for SRY gene alone does not help us to know if a person is a male or a female.
A person with
Androgen Insensitivity Syndrome (AIS) starts off on a path of becoming a male activated by a functional SRY gene; however, somewhere along the sexual developmental process things go wrong. A genetic mutation in the
androgen receptor (AR) gene results in defective cell receptors and these receptors fail to recognize androgens (male hormones, such as testosterone) that are responsible for the proper development of primary and secondary sex characteristics. The androgens are present in the body, but because of defective receptors the cells behave as if there were no male hormones (similar to normal women). Consequently, the testes remain inside the abdomen and the normal male external genitalia are not formed. When the sex-determining cells do not receive androgen signals, there is a switch to development of some female features. Patients with AIS do not have uterus and ovaries hence they cannot have menstruations after puberty, but they develop external genitalia somewhat similar to those of normal women.
All humans produce both male and female sex hormones. Women have androgens and men have estrogen (female hormone), but the amount is small enough so as not to confuse the body’s development. Normal men and people with AIS have equal amounts of estrogen, but the higher amounts of androgens cancel out the effects of the estrogen in men whereas in AIS who are unresponsive to androgens go on to develop breasts like women because the estrogen effect is not cancelled. Facial and chest hair are dependent on testosterone and since people with AIS cannot process testosterone, they do not have beard and chest hair. The growth plates in long bones (arms and legs) of people with AIS fuse later in life and hence they continue to grow in height for a longer period than normal children thus resulting in them being tall.
Over 200 genetic mutations have been described and the mutation result in various subtypes of AIS. The primary and secondary sexual characteristics differ in the subtypes of AIS and are dependent on the increasing amount of tissue responsiveness to androgens. People with
complete AIS have external features of normal women. The testes are in the abdomen, there is a small vagina and no penis or scrotum, and they have sparse pubic and axillary hair at puberty.
Partial AIS results in female body, slightly virilized (maleness) genitalia and increasing amounts of axillary and pubic hair. People with
Reifenstein Syndrome (a form of AIS) have tissues that respond to some extent to androgens and it results in ambiguous genitalia, small testes in abdomen or in a small scrotum, and small breasts after puberty. Surgical removal of testes and waiting for a couple of years will result in effect of androgenic-developed muscles to go away, and muscle mass and strength become similar to normal women. As tissues become more and more responsive to androgens in minor forms of AIS, the external features become more male-like and problems may be seen in only decreased sperm counts or breasts larger than seen in normal men.
People with complete AIS are assigned a female gender at birth and their upbringing and gender role are thus that of a girl/woman. Diagnosis is usually made by finding testes in inguinal canal or hernia. Menstruation does not occur at puberty, but in case of an elite athlete it is often attributed to intense athletic training. Testes are surgically removed since testes located in abdomen are at a higher risk for developing cancer. Female hormones are given once children reach adolescence and adulthood. Psychological counseling is paramount for the person with AIS.
People with partial AIS have greater problems because the genitalia is somewhat virilized (male-like) and the child may have been raised as a male or a female. They require reconstructive surgery of the genital area and will need to take male or female hormones after puberty depending on the gender chosen. Psychological trauma is great in them.
Coming up next:
1. Other forms of conditions where there is an ambiguous genitalia and assigning of gender is problematic.
2. Gender assignment in sports
3. How sports officials cheat; make life more difficult for athletes, and is there a conspiracy in athletics? (And you thought that only a very respectable Sports-India member can see conspiracy when other members don’t!
)