If a child is born with sickle - cell anaemia then his /her parents must be :

Options

A. Homozygous
B. Heterozygous
C. Co - dominant
D. Nullizgous

Answer

To determine the genotypes of the parents of a child born with sickle cell anemia, we can follow these steps:

### Step 1: Understand Sickle Cell Anemia
Sickle cell anemia is an autosomal recessive disorder. This means that a child must inherit two copies of the sickle cell allele (let's denote it as "s") to express the disease. The normal allele can be denoted as "S".

### Step 2: Determine the Child's Genotype
If a child is born with sickle cell anemia, their genotype must be "ss" (homozygous recessive). This indicates that the child has inherited one sickle cell allele from each parent.

### Step 3: Analyze Possible Parent Genotypes
For the child to have the genotype "ss", both parents must contribute a sickle cell allele. The possible genotypes for the parents can be:
1. Both parents are heterozygous (Ss).
2. One parent is homozygous recessive (ss) and the other is heterozygous (Ss).
3. One parent is homozygous recessive (ss) and the other is homozygous dominant (SS) is not possible, as the dominant parent cannot pass on the sickle cell allele.

### Step 4: Conclusion on Parent Genotypes
Since the child has sickle cell anemia (ss), at least one parent must carry the sickle cell allele. Therefore, the most likely scenario is that both parents are heterozygous (Ss) or one parent is homozygous recessive (ss) and the other is heterozygous (Ss).

Thus, we conclude that the parents must be either:
- Heterozygous (Ss) and Heterozygous (Ss)
- Heterozygous (Ss) and Homozygous recessive (ss)

### Final Answer
The parents of a child born with sickle cell anemia must be heterozygous (Ss) or one parent could be homozygous recessive (ss).

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