A man and his wife are both heterozygous for the sickle cell trait. The likely...

Explanation

This question is asking about the probability of a man and his wife who both have the sickle cell trait having offspring that are either carriers or sicklers. Sickle cell trait is a genetic condition where a person has one normal hemoglobin gene and one abnormal hemoglobin gene. If a person inherits two abnormal hemoglobin genes, they will have sickle cell disease. Since both parents are heterozygous, it means they have one normal hemoglobin gene and one abnormal hemoglobin gene. When they have offspring, each parent will randomly pass on one of their genes to their child. Using a Punnett square, we can determine the probability of their offspring inheriting the sickle cell trait. In this case, the Punnett square would have the letters S and s representing the normal and abnormal hemoglobin genes, respectively. The possible combinations of genes in their offspring are SS, Ss, and ss. The probability of having an offspring with the sickle cell trait (Ss) is 50%. This is because there are two possible ways to get the Ss genotype: either the child receives the S gene from the father and the s gene from the mother, or the child receives the s gene from the father and the S gene from the mother. The probability of having an offspring with sickle cell disease (ss) is 25%. This is because the child must inherit the s gene from both parents. Therefore, the likely percentage of their offspring that will either be carriers or sicklers is 50% + 25% = 75%. This makes option A the correct answer. It's important to note that this question is based on Mendelian genetics, which is the study of how traits are inherited from parents to offspring. It is also important to know about genetic counseling and testing for sickle cell disease, especially for couples who are both carriers.