Yes, it does happen in a small number of people. This is just a guess, but I have a sick feeling that we will see more of this (no vaccines involved) with our future generations. The damage lies mainly in our genes - it is true that it is genetic - to an extent. There are so many scenarios though to sort through I am finding. Here are just some things to consider....
How much toxic exposure the parents, grandparents, and other previous generations endured....our cells are damaged by chemicals and some viruses (my guess is that only manufactured viruses will do this). We inherit our parents' DNA - which is made up of billions of cells....some already damaged from the moment of conception. When there is damage to the cells, your body cannot operate accordingly.
Mercury fillings in the mother's mouth play a role. The baby is exposed to this toxic mercury throughout the pregnancy if the fillings are leaching the toxin into her system.
Viruses passed on at the moment of conception play a role - Lyme, Herpes, and many more. The mother is suffering from them usually and passes them onto her baby. The mother is generally misdiagnosed with fibromyalgia or chronic fatigue syndrome. There are also the vaccines administered during pregnancy to consider.
The mother may be suffering from an undiagnosed thyroid disorder. Conventional medicine rarely tests correctly and even then, the scores are "inflated". The thyroid disorder is passed to the child. Your thyroid is everything.. ..if it is not functioning properly it can affect hormonal balance, copper levels, nutritional absorption, etc. Prescription drugs can kill your thyroid. So can other chemicals.
Many children suffering from Autism are found to have thyroid disorders and copper toxicity.
What is boils down to I am finding is the correct detox program for you as an individual. We need to heal the gut and get everything back in balance. I was also told that it could take as many as 3 generations (completely unvaccinated) to undo this mess. I don't know if that is true or not, but it gives me chills thinking about it.