There's interesting research about the association of having a grandfather who conceived your parent when they were older than 50 and there being an increased likelihood for the grandchild to have, or to be, in the autism spectrum. This was a study done in Sweden and it was going back and looking at the Birth cohort and they found that children with autism had grandfathers, or were more likely to have older grandparents, not just parents. This was interesting, and we know this about women conceiving later, so what is the possible cause or hypothesis? Well, genetics is being looked at, and this concept of genetic mutations because of environmental or this concept of epigenetics, where environment affects genes.
And since we know that it is not just one gene but actually a cascade of genes, possible, what they call, De novo mutations, that’s something changed along the line. And as parents get older, as the father gets older, changes in the sperm in some way and the DNA, or in some variation that took place over time and it was related with age. So although the increase is really a small amount, there was an interesting association, and the fact that there was environmental impact on genes, that theory is getting supported. It's interesting, but it's also only really a small increase, and it's really an association, but interesting research.