Statistics help- Sampling Distibutions

Its believed that 4% of children have a gene that may be linked to juvenile diabetes. Researchers hoping to track 20 of these children for several years test 732 newborns for the presence of this gene. What's the probability that they find enough subjects for their study?

So far I have:
n=732 p=.04 q=.96

Now idk what to do. Help!

we assume binommial distribution
p(x<=20) is cumulativeP(20;732;0.04)=0.043
so P(x>20)=1-0.043= 0.957