The control side was 54 males without autism and 67 females without autism.
Maybe 34 is enough to get that statistical conclusion, but it seems pretty small. It's based on recall of if they had -frequent diet drinks- (edit: cutoff variable was one single diet drink per day) during pregnancy, so it might be being determined by like 15 people for the female side that were diet drink users and more for the controls, further divided by 6 different demographic subsets? Will try and find that number.
I feel like there are things not being said in the study that should have been. I could be wrong, but I don't see a mention of whether the parents of the autistic children were themselves autistic or not and feel that could be important criteria to have noted.