The best way to look at that is if you look at the world records for the 1 mile from 1880 through to the modern day. They improved by about 1% every four years. So if I can improve your performance by 1%, I put you four years ahead of everybody else. So if you're not quite that good, I put you as good as everybody else. If you're really good, I put you four years ahead of where the rest of the people are going to be with modern training methods and so on.

Amphetamines do the same thing for focus.

What are some of the side effects for adult players?

This is the question. We don't really know. Obviously, people don't admit and we haven't been able to follow people taking steroids over a long period of time. The potential of liver damage is clearly one of those [risks], because steroids have a first pass through the liver. In addition ... there's a question of whether it would increase neoplastic disease [cancer], either in the prostate or in other parts of the body.

If the use is relatively short-term, a couple of years, the effects may be minimal. Lots of sports players who've done this are turning up with diseases and problems.

We need some major, good studies looking at long-term effects within sport.

Amphetamines certainly create high-strung behaviors, bizarre behaviors, much more than any of the other drugs

In women, [steroids have] huge effects on hirsutism (excess hair) and effects on potential reproductive ability. Female athletes do it; they just seem to be less likely to be caught at the moment.

How widespread are these drugs among younger players?

We don't know. If I'm a young boy, or young girl for that matter, and I'm looking to be successful -- and when you're young, you really care about winning -- and when you see your heroes doing this, they become a role model. That's a very bad role model.

I think we've got a problem because as you go to younger kids, clearly this is not something you want to be doing and certainly, around puberty this could be a total disaster.

What are some of the side effects for younger players?

Younger players you can get alterations in growth, in particular. The other big potential effect is the effect on behaviors, the so-called " roid rage."

How young are some players starting?

I think we've got people -- 12-, 13-, 14-year-olds -- who certainly see this as something that's worthwhile.

What would you want parents to keep an eye out for if they have a young athlete?

If they've got a young athlete and his muscles suddenly go up dramatically, that's probably the single best way to look for most of these drugs. Behavior changes in puberty -- all behavior changes don't mean they are taking drugs.

The big thing is if a person is suddenly bulking up. It doesn't come without working, as well. It's a combination of the person who starts to work out a lot but taking a steroid. Somebody whose performance goes up dramatically -- they were the sort of the middle of the pack and they're suddenly at the top. Now, this may be a normal growth spurt, but those sort of things, as a parent you've got to be suspicious that maybe your kid is doing something.

And if they do have those suspicions, what do they do?

You can go to the physician and have them tested for these drugs, just the same way as the sports authorities test for the drugs. Basically, the physician can send off tests for these drugs. I'm not saying that's what they should do, but I think that's what I would do if I felt it was important.

Do they drug-test young players in high school?

They usually don't. I think we're going to see more and more of this happening. The other group who don't [get tested] are the masters athletes, the people over 60. It's clearly something that stretches through all ages, into old age.

Are all performance-enhancing drugs illegal?

No. A number are very legitimate. We should not throw out the baby with the bath water.

How do you test for these drugs? Can you test for all of them?

The tests for growth hormone, at the moment, are very poor. The Olympic Committee is hoping that this year they will have an adequate test for growth hormone.

The tests for the others begin usually with a urine test looking for alterations in the urine testosterone ratio. All of them will affect that ratio. If that looks abnormal, the modern testing is now do to NMR scanning [nuclear magnetic resonance spectroscopy] and you can actually pick up the peaks, the abnormal peaks, of the different compounds. Most of those are known.

Where you can get away with it is if you have a compound that nobody actually knew existed.

We've got to recognize that there are a whole new set of ... pills that are being developed to help people in rehabilitation following surgery. And all of these are, quite honestly, much more powerful. They can be taken orally. They have less side effects, and my assumption is that now that most of the steroids are gone, that people are going to find a way to get growth hormone and the next thing you'll see is this large new class of drugs, these selective androgen receptor molecules [SARMs] -- will be used by the athletes. Many are in phase I and phase II trials.

As for the tests for the things we can test for now, how accurate are those tests?

They are very, very accurate.

How do SARMs work?

Basically, they combine with either the testosterone or the dihydrotestosterone receptor and they activate it, but they do it by a nonsteroidal mechanism.

The other [class of drugs being developed] are the anti-myostatins.

Myostatin inhibits the growth of muscle and if you can block that, you will put on an extra 10% of muscle so you will bulk out pretty quickly, and there are drugs that are being developed by a number of companies now that are in phase I and phase II trials, and so that becomes yet another way to bulk people out.

There's a little boy in Germany who basically has a spontaneous myostatin deletion [a gene glitch] and he's extraordinarily strong at 5 years of age.

So all of these things are happening, and there's a very legitimate need to use these drugs if you get away from sport. For older people with disease, there's clearly a legitimate need to develop drugs that can strengthen you and allow you to function.

What else would you want to add about the topic?

We as a society have to decide what do we want out of our sports people. Do you want them to be superheroes? Is that what we really want, or do we just want to see people just playing to the best of their ability?

I think the public has spoken with their checkbooks. Over my lifetime, sports has gone from something that was not a huge moneymaker to an incredibly huge moneymaker. We're not paying to go watch the backyard players play anymore. We're paying to watch superstars and who are so much better than any of us. And there is a price to pay and it's going to come in performance-enhancing drugs.

I don't think that there's any belief that this hasn't been going on in every one of our professional sports over the last 20 years.

I would argue that this is not a new phenomenon. It's a new phenomenon for steroids.