Probability Binomial With Parameters

"Among Orthodox Jews, families are expected to be large. Among Ashkenazim, a segment of the Jewish population, Tay-Sachs disease is [TSD] a relatively common disorder. TSD is an inherited autosomal recessive disorder, i.e., both parents must be carriers in order that a child inherits the disease. Suppose 2 such Ashkenazim parent-carriers have 12 children. What is the probability that: [1] No children will have TSD? [2] At least 1 child will be born with TSD? [3] No more than 2 children will have TSD? "