Answer:
Yes, 50% homozygous vs 50% heterozygous
Explanation:
Let dominant sickle cell allele be represented by an allele A while the recessive form be represented by S.
A person that is homozygous dominant for the trait will be AA genotype.
A person that is heterozygous for the trait will be AS genotype.
A cross between the homozygous dominant and heterozygous will be:
AA x AS
The F1 offspring will be AA, AA, AS, and AS (See the Punnet's square result)
Recall that: AA produce all normal-shaped hemoglobin molecules. Hence, 50% of the offspring will produce all normal-shaped hemoglobin.
Also, the ratio of homozygous to heterozygous offspring is 1:1, equivalent to 50% homozygous vs 50% heterozygous.
Therefore, considering the questions;
Will any of their children produce only abnormal hemoglobin? The answer is yes.
What percentage of their offspring will be homozygous versus heterozygous? The answer is 50% versus 50%