I give an example. There is a drug called GW 501516. It works well at helping with endurance so some cyclists and athletes take it.
One Olympic champion has been banned for taking it.
Trouble is that research on the drug for medical use was stopped when it is was found to cause cancer in rats.
Basically if you legalize doping you have to accept that sportspeople will take anything that helps them to win.
If you have children then a parent must accept that the only way your child will become successful is to feed him or her massive doses of steroids or EPO or whatever drug which may effect their health or even kill them,
If a person is happy to do that then they really should not be allowed to have children,
Anti-doping today is bad but the thought of people taking anything they want to take scares me. If that ever happened I hope all sports would be banned forever.