Sex Testing of Women Athletes The Story of Olympic Silver Medalist Santhi Soundarajan

Santhi’s Story http://www.ibnlive.com/videos/28851/how-are-athletes-gender-tested.html Santhi Soundararajan won the silver medal in the 800-meter race at the 2006 Asian Games in Doha, Qatar. Following her silver medal performance, her sex was officially questioned. On December 18, 2006 Santhi was stripped of her medal based on the results of gender determination testing

How is sex determined in humans? Anatomy: Primary and secondary sexual characteristics - genitalia, body hair, pelvis, etc. Physiology: Function and interaction of the sex organs including concentrations of sex hormones such as estrogen, progesterone, and testosterone. Genetics: Type and number of sex chromosomes (e.g. X or Y) and/or genes (e.g. SRY)

Question: Could Santhi have an XY karyotype and be female? A: No, an XY individual is always male. B: Yes, this is common. C: Yes, if a male-determining control gene is missing on her Y chromosome.

Transition Slide Read the “History of Gender Testing for Olympic Athletes” in your lab packet The Case You are part of a team of doctors which includes a gynecologist, endocrinologist and psychologist charged with examining Santhi. Your team is responsible conducting both physical and biotechnological examinations of Santhi in order to correctly identify her gender.

The Tests Your team will run four tests: Physical exam – analyze the results of physical / anatomical tests Abbott Testosterone ELISA – Enzyme Linked ImmunoSorbant Assay that measures the amount of testosterone hormone in a sample and works by using an antigen-antibody immune reaction Karyotype – identifies the gender of an individual based on chromosome set Gel Electrophoresis – analyzes a sample for the presence of the SRY (male determining gene) located on the Y chromosome

Santhi’s Karyotype

Santhi’s DNA Gel

Sources of Genetic Variability in Meiosis Independent Assortment Each pair of homologous chromosomes lines up at Metaphase I plate. There is a 50:50 chance that a daughter cell will get one or the other copy of the chromosome. Animation: http://wps.prenhall.com/wps/media/objects/487/498795/CDA10_2/CDA10_2b/CDA10_2b.htm

Crossing Over Crossing over can occur anywhere along the autosomes. In males, the sex chromosomes (X and Y chromosomes) normally cross over only at their tips.

How is Sex Characterized in Humans? In addition to anatomy, physiology, and chromosomes, there is a 4th answer: Genes: Specific genes determine whether an embryo will develop as a male or female.

SRY (Sex- Determining Region of the Y chromosome) Gene Early in development, the immature gonads of males and females are indistinguishable. Males: In the 7th week of development, the SRY gene on the Y chromosome activates a number of genes, and the gonads develop as testes. Females: With no SRY gene, gonads develop as ovaries by default. SRY gene Y X

Can you have an XX male or XY female? Watch this video: http://www.hhmi.org/biointeractive/media/meiosis-lg.mov What sex is XX (SRY+)? What sex is XY (SRY-)? Sex reversal occurs in 1 in 20,000 births!

If you were a member of the Asian Games medal committee and Santhi’s karyotype revealed that she is XY and SRY-, what would you do? A: She has female genitalia, allow her to keep her medal. B: She is genetically male, take her medal away. C: Perform additional tests.

What do you think about requiring gender testing for female athletes in international competition? A: It should be banned because gender determination is so complex. B: It is necessary to ensure an even playing field. C: It is necessary, but needs to include a large number of genetic tests to ensure fairness. D: It should be required for all athletes, both male and female.

What about Santhi Soundararajan? Santhi was stripped of her silver medal. An anonymous official in the know has reported that Ms. Soundarajan's tests revealed more Y chromosomes than are usually present in the genetic make-up of a female. No official statement has been made.