Other than the studies done on children who had autistic parents, recently a couple of studies were done on children who either had a sibling or a twin showing autistic signs. Similar to the outcomes in the autistic parents studies, most children having autistic siblings/ twins were found out to be showing autistic signs. According to a recent study, around fifty percent of infants with autistic siblings showed some kind of atypical behaviour, around one forth of them showed delays and deficits in achieving infancy milestones and around 17% of all were later diagnosed with ASD (Autism Spectrum Disorder).