This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Genetic and genetic disorders, Subject name: Pediatrics
[{'content': 'An effected male infant born to normal parents could be an example of all of the following, except \nSelect and explain. \nA. An Autosomal Dominant disorder, B. An Autosomal Recessive disorder, C. A Polygenic disorder, D. A Veically Transmitted disorder', 'role': 'user'}, {'content': 'Answer: A \nExplanation: An autosomal dominant disorder if present in the parents will always express itself phenotypically. So it is not possible for normal parents to have an child affected with an autosomal dominant disorder. Reference: GHAI Essential pediatrics, 8th edition', 'role': 'assistant'}]