A woman who is a carrier of haemophilia (XᴴXʰ) has children with an unaffected man. The probability that a son is affected is

  1. 0.5
  2. 1
  3. 0
  4. 0.25
Answer

A) 0.5

Sons receive X from the mother: half get Xʰ. AS & A Level Biology · Topic 16 Inheritance · 16.2 The roles of genes in determining the phenotype

Biology MCQ · More A Level Biology: Inheritance MCQs · Practise