Who are the cheaters? Again, by and large they are not the dominant figures in their sports; they're the the wanna-bes, the almost-weres, and a fair number of has-beens. Indeed, even the 40-year-old Bonds might well have retired by now, far short of Hank Aaron's career home run record. In cycling, at least, there are indications that the most rampant cheating takes place in the amateur ranks, where riders are desperate to make the pros. In the past few years, literally dozens of European amateurs have dropped dead from suspicious causes, some as young as 20 years old.
I think this is comforting nonsense. For female athletes in particular, the benefits of male-like blood chemistry are enormous, enough to take someone from the middle of the pack to the top of the pack. A female athlete has the same basic tissue structure as a male athlete -- all they're missing is some chemistry.
In contrast, this may not be true for young male athletes. I suspect most young ultra-elite male athletes are working near the limits of human tissue structures. Revving the engines may have little effect and may even decrease performance.
Men in their 30s and 40s though, are more like the female situation -- their chemistry is in decline and their core potential may be underutilized. Of course their hearts and vessels may not survive the stress of a youngster's chemistry.