Which of the following is NOT a biological factor associated with autism spectrum disorder?

• A. Exposure to certain vaccines
• B. Parental age at conception
• C. Genetic mutations
• D. Prenatal exposure to certain drugs

Answer: (A)

Verified step by step guidance

1. Step 1: Begin by understanding the context of autism spectrum disorder (ASD). Autism is a neurodevelopmental condition influenced by a combination of genetic, environmental, and biological factors.
2. Step 2: Review each option provided in the question and assess whether it is a biological factor associated with ASD. Biological factors are those that directly impact the physical or genetic development of an individual.
3. Step 3: Analyze 'Parental age at conception.' Research shows that advanced parental age, particularly paternal age, is associated with an increased risk of ASD. This is considered a biological factor.
4. Step 4: Examine 'Genetic mutations.' Genetic mutations, such as changes in genes involved in brain development, are strongly linked to ASD. This is also a biological factor.
5. Step 5: Evaluate 'Prenatal exposure to certain drugs' and 'Exposure to certain vaccines.' Prenatal exposure to drugs like valproic acid has been associated with ASD, making it a biological factor. However, exposure to vaccines has been extensively studied and shown not to be associated with ASD. Therefore, 'Exposure to certain vaccines' is NOT a biological factor associated with autism spectrum disorder.