Anish is having colour-blindness and married to Sheela, who is not colour-blind. What is the chance that their son will have the disease?

Options

A. `100%`
B. `50%`
C. `25%`
D. `0%`

Answer

To solve the problem of determining the chance that Anish and Sheela's son will have color blindness, we can follow these steps:

### Step 1: Understand the Genetics of Color Blindness
Color blindness is a sex-linked recessive trait that is carried on the X chromosome. Males have one X and one Y chromosome (XY), while females have two X chromosomes (XX).

### Step 2: Determine the Genotypes of Anish and Sheela
- Anish (the father) is color-blind, which means his genotype is X^cY (where X^c represents the X chromosome with the color blindness allele).
- Sheela (the mother) is not color-blind, and since we don't have information about her being a carrier, we assume her genotype is XX (both X chromosomes are normal).

### Step 3: Determine the Possible Gametes
- Anish can produce two types of gametes: X^c (color-blind) and Y (normal male).
- Sheela can produce two types of gametes: X (normal).

### Step 4: Create a Punnett Square
Now, we can set up a Punnett square to determine the possible genotypes of their son:
```
Sheela's Gametes
X X
Anish X^c | X^cX | X^cX
Y | XY | XY
```

### Step 5: Analyze the Offspring
From the Punnett square, we can see the possible genotypes for their son:
1. X^cY (color-blind son)
2. XY (normal son)

### Step 6: Calculate the Probability
Out of the two possible outcomes for their son:
- 1 outcome is color-blind (X^cY)
- 1 outcome is normal (XY)

Thus, the probability that their son will be color-blind is 1 out of 2, or 50%.

### Final Answer
The chance that Anish and Sheela's son will have color blindness is **50%**.

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