Why do feds try to learn details linked to private life of some athletes?

Several athletes that are suspected of steroid use become targets of the government. Federal prosecutors do almost anything in order to learn whether some athletes have administered any doping products. They don’t spare taxpayers’ funds for this goal. Much money is spent to learn even private life of sportspeople. According to the government, certain details of their private behavior can disclose the truth about administration of forbidden medicines. So, girlfriends of some sportspersons are interviewed by federal prosecutors.
For example, it has been revealed that former girlfriends of Lance Armstrong and Roger Clemens and a former mistress of Barry Bonds have been asked about several details linked with private life of these athletes. Which questions were asked?
Kimberly Bell, a former mistress of Barry Bonds, was asked about testicles of this athlete. She reported that the baseball player’s testicles were shrunken. So, her affirmations served as an argument that Barry Bonds used steroids and/or other banned preparations.
It is known that testicular atrophy belongs to adverse consequences of some steroids. Thus, the government decided to learn whether Barry Bonds had had this problem. But it is an unreliable argument in order to prove that anyone has applied several prohibited drugs. Steroid users may prevent this unwanted reaction, if they administer several preparations for this purpose.
Mindy McCready, a former mistress of Roger Clemens, was asked whether this former baseball player had suffered from erectile dysfunctions. The woman affirmed that sometimes Roger Clemens had suffered from this problem.
As for erectile dysfunctions, they may occur during administration of steroids. But if you study information about undesirable effects of steroids more attentively, you can understand that this effect is more likely to appear after discontinuation of usage. It happens because natural testosterone secretion is normally suppressed by usage of exogenous testosterone. But since there are such medications that are able to restore natural production of testosterone, erectile dysfunctions can be avoided.
Sheryl Crow, a former girlfriend of Lance Armstrong, was also targeted by federal prosecutors. But questions are not disclosed. According to some suggestions, she might have been asked also about sexual abilities of the cyclist.
In fact, federal prosecutors have a mistaken opinion in this case. However testicular atrophy and erectile dysfunctions may occur because of steroids, these arguments are not reliable.