This is something that I have thought a lot about. I have one step daughter with ADHD and I have three biological children the youngest is Sarah who was diagnosed with Autism.
My step daughter was born in 1984. My 2 biological daughters were born in 1985 and 1987 and they had no health issues. Sarah was born in 1989.
Therese K. Grønborg, M.Sc., of Aarhus University, Denmark, and colleagues conducted a population-based study in Denmark of all children (about 1.5 million) born between 1980 and 2004. They identified a maternal sibling group derived from mothers with at least two children and a paternal sibling group derived from fathers with at least two children.
“To date, this is the first population-based study to examine the recurrence risk for autism spectrum disorders (ASDs), including time trends, and the first study to consider the ASDs recurrence risk for full- and half-siblings,” the authors note in the study.
The study results suggest an almost seven-fold increase in ASDs risk if an older sibling had an ASD diagnosis compared with no ASD diagnoses in older siblings. In children with the same mother, the adjusted relative recurrence risk of 7.5 in full siblings was significantly higher than the risk of 2.4 in half siblings. In children with the same father, the adjusted relative recurrence risk was 7.4 in full siblings and significant, but no statistically significant increased risk was observed among paternal half siblings, the results also indicate.
“The difference in the recurrence risk between full and half siblings supports the role of genetics in ASDs, while the significant recurrence risk in maternal half-siblings may support the role of factors associated with pregnancy and the maternal intrauterine environment in ASDs,” the study concludes.
This is a very interesting study. I no that our middle daughter is watching her two sons to make sure they have known Autistic characteristics. We had Sarah’s DNA checked and they said that there is no abnormalities in her DNA to cause her diagnosis.
- Determining Child’s Risk When Older Sibling Has Autism (webmd.com)
- Autism is shared among siblings, study finds (sacbee.com)
- Recurrence risk for autism spectrum disorders examined for full, half siblings (eurekalert.org)
- Study reveals negative effects of half-siblings (medicalnewstoday.com)
- Determining Child’s Risk When Older Sibling Has Autism (news.health.com)
- Half-Siblings More Likely to Start Unhealthy Habits in Life Early (scienceworldreport.com)