Male to female is the most common.

The Olympic committe now allowing transgenders to compete.

Is this fair? Or it is discrimination to not allow them?

Take a look inside the interesting world of transgender athletes

Heidi Krieger

One of the few female to male transgenders in sporting, Andreas story differs greatly from many others.

Born Heidi Krieger in 1966 in Berlin, Krieger is a shot putter, who competed as a woman with the East German athletics team. In 1986 as a woman, he won the European Championnships.

In 1997 he underwent sex reassignment surgery and changed his name to Andreas. This surgery was by all accounts, to finsish a process which began a long time prior.

From his mid teen years, Krieger was unwittingly fed massive doses of steroids by East german sporting officials.

Records show that in 1986, the year in which she became European champion, she was given 2,590 milligrams of Oral-Turinabol by her coach, which is roughly 1,000 milligrams more than the amount given to the Canadian athlete Ben Johnson.

His gold medal from the European Championships now forms part of a trophy which is awarded annually to Germans involved in the fight against doping. Krieger has also filed a lawsuit againest Jenapharm, the company which produced the steroids on the orders of the East German government during the 1970s and 1980s.

Krieger is quoted as saying "They killed Heidi. For me the tragedy is still that I had no choice in determining my sexual identity, the drugs decided my fate"

Mianne Bagger

Miane Bagger is the first male-to-female transgender golfer to play professionally.

She was born in Denmark in 1966, and emigrated to Australia in 1979, where she presently splits her time between Adelaide and Perth.

As the Australian Amateur Golf Association had no existing rulings againest transgenders, Bagger was allowed to compete and won the South Australian Championship in 1999, 2001 and 2002. She was ranked as high as 6th on the Australian amateur golf circuit.

At the time this caused controversy, with strong arguments on both sides.

In 2003 she played in the Australian Women's Open and attempted to join the Australian Ladies Professional Golf [ALPA] tour. In 2004 she was admitted.

As of 2008, Bagger is still unable to compete in the US based LPGA as they maintain a 'female at birth' entry condition.

Michelle Dumaresq

Renee Richards

Renée Richards was born Richard Raskind in 1934 in New York City.

In 1975, at age 41 she underwent sex reassignment surgery.

She is one of the most well known trandgenders due to her winning a lawsuit after being initially being denied entry to the 1976 U.S. Open.

After her bar Richards disputed the ban, and the New York Supreme Court ruled in her favor in 1977.

While studying at Yale, Richards played tennis and captained the team in 1954 - as Richard Raskind. Also, playing as a male, she reached the finals of the mens national championships in the 35 and over division. She married and fathered one son Nicholas Raskin, while male.

She began playing as a female in 1977, at first incognito until her real identity was discovered.

Richards was ranked as high as 20th overall at one point and her greatest successes on court were reaching the doubles final at the 1977 U.S. Open in 1977 with Betty Ann Stuart and winning the 35-and-over women's singles in 1977.

Richards has written two books, and presently runs her own medical practice.

Hermann Ratjen

Competing as Dora Ratjen "she" finished fourth in the high jump category in 1938.

This went undiscovered for almost 20 years.

In 1955, "Dora" then going by the name Hermann Ratjen, claimed that the Nazis had forced him to enter the 1936 Olympics as a woman.