I agree that there are "triggers". But first thing first. we need to look at those "triggers" that might have attacked a fetus's immune system or "locked themselves in a gene/s" in Utero first. There are viruses out there, which may not produce major illness symptoms in "a prenatal mom" but can produce severe irrepairable damages to gene/s at the time of conception. E.g: Herpes simplex virus or CMV or HIV or Rubella/Mumps/Measles virus/Pertussis virus etc. Please note that most of the viruses are "airborne", which means they are out there in AIR 365 days a year. We just can't see them, but can inhale them very easy, when we breathe in. Vaccines do not cause or trigger autism. In order for a child to have any kind of MAJOR DISABILITY LIKE AUTISM, the risk factors that were mentioned above have to be taken into consideration first. Genetic disorders are occuring in kids, due to several things going wrong before or prior to their birth. It does not necessarily hold a "mother" solely responsible. Because, there are environmental toxins, chemicals, viruses radiation hazards, contamination of several things that might have happenned that we as mothers, do not recognize them at that time of 280 days of gestation. I hope this clarifies a bit. I am not into "vaccine theories" of autism. so, I suggest that if you are into believing that theory, I have no further explanations about it. You may want to talk to geneticists who can explain these things better. Good luck.