http://www.pnas.org/cgi/content/full/94/16/8380

http://cat.inist.fr/?aModele=afficheN&cpsidt=15380275

http://list.web.net/archives/mnchp-l/2004-April/000508.html

http://press.psprings.co.uk/jech/october/851_ch45179.pdf

http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=pubmed&cmd=Retrieve&dopt=AbstractPlus&list_uids=16108999&query_hl=1&itool=pubmed_docsum

Autism has been connected to much older parents since before 1980. Schizophrenia has been observed in children of older dads since 1958.

Genes have changed that much over the past 20 years, huh?

Same observation, regards rates of obesity. Has “the fat gene” gone wild over the past 2 decades?

I don’t think so.

However, rates of homosexuality (as in the attraction, not how it is expressed) appear to have been stable across a very long time, and cutting across all cultures and types of families.

And therein lies a difference…

And then statistical artifact (this one is possibly true of the older brother effects as well): “Not an especially interesting finding,” said Eric Courchesne, director of the Center for Autism Research at the San Diego Children’s Hospital.

It is unlikely this finding will have any significant impact on neuroscience research or on early identification or treatment of autism, Courchesne said. “The study says nothing about the brain bases and nothing specific about the genetics or possible environmental factors that may cause the condition,” he said.

In fact, Courchesne thinks the finding might be a statistical fluke. “Autism is a heterogeneous disorder, and when you get a huge enough sample, even small and possibly irrelevant statistical associations may be found,” he said.”

This would be consistent with the older brother effect, not a contrasting comparison.