Yale researchers examined placenta tissue samples that were saved from various research hospitals. The research is based on past work showing the connection of abnormal cells that diagnosed other genetic defects such as Down Syndrome. It was a small sampling of 13 cases of children that were later diagnosed with autism and 61 samples from neurotypical children. All 13 cases showed some sort of abnormality. The researchers suggest that there may still be children with normal placentas who are diagnosed with autism later in life. But two things can come of further research. One, that children born with older siblings with autism can be screened and parents whose children do show abnormalities can be educated early on for warning signs and intervention could happen earlier. The only concern I see is that further research needs to done. It is such a small sampling and parents have enough worries that they don't need to be worrying about something that may not be. For further information go here and here.