This episode reveals the danger of denial. It's natural to wish you didn't have an illness, and most people hope their own serious sickness or that of a loved one is the exception to the rule and won't require treatment. Fortunately, most people don't let their wishful thinking get in the way of common sense. They find a good doctor and get treated.
Sadly, a very small minority of patients and relatives allow their natural initial denial to become denialism, a mindset that refuses to accept reality under any circumstance. They insist that their condition is not real or that unproven treatments will cure it. They surround themselves with other people, usually found on the internet, who agree with them. They even manage to find doctors who either share their medically ridiculous beliefs or are unethical enough to prey on their patients' ignorance.
This episode is loosely based on a similar case from California. An HIV-positive woman named Christine Maggiore convinced herself that HIV was harmless after speaking with a scientist who has become infamous for his strange and unsupported idea that HIV doesn't cause AIDS. She took his advice and didn't take medications. She had two children and didn't take any steps to keep them from getting infected at birth. She breast-fed them, although breastfeeding is a major source of mother to child transmission. Her daughter got HIV and died of AIDS-related pneumonia, three years old. Maggiore herself died soon after this episode aired, in late 2008.
As revealing as "Retro" is, it doesn't quite present what actually happens in cases like these, since the show delivers justice in a much more satisfying way than real life. In the episode, the bad doctor is punished. In reality, the doctors who went along with the mother's denial got nothing but a slap on the wrist. And the bad scientist who initially convinced Ms. Maggiore that HIV was harmless, and also advised the South African government's disastrous AIDS policy that resulted in over 300,000 needless deaths, is still a tenured professor, still telling lies about AIDS, protected at his posh university by administrators who care more about political correctness than human lives.