Worldwide, the proportion of male births is about . Autoimmune thyroid disease (AITD) occurs more often in females than in males. Researchers wondered whether families with a child who has AITD have a different male-to-female ratio among siblings compared to the general population. They collected records from families with a child diagnosed with AITD. Among the cases, were male and were female. The male AITD cases had male siblings and female siblings. The female AITD cases had male siblings and female siblings. If there are a total of male siblings in the study, how many female siblings are there?
