That's a part of the story, women having kids layer in life and fewer kids overall is part of the story, Tylenol use might be part of the story, vaccine schedules and ingredients might also be part of the story,
But if you talk about any one of those things as contributing to autism rates, someone is going to say it's garbage science because it doesn't explain everything, or it makes women feel accused of making bad decisions or confronted with the consequenses of their actions, or it makes a republican look good, or one of the establishment heros look bad. That's just the state of the world any more.
I was 21 when my son was born and after the first trimester I drank and smoked. He’s 6’3, healthy, an athlete with excellent scholastic record.
I probably stunted his growth but at least he doesn’t have to constantly duck to get through doorways.