The sex of the child is determined

Options

A. At the time of fertilization on the basis of kind of sperm
B. After cleavage
C. At the time of birth
D. The kind of ovum that fertilizes with sperm

Answer

### Step-by-Step Solution

1. **Understanding Chromosomes**: The sex of a child is determined by the combination of sex chromosomes contributed by both parents. Males have one X and one Y chromosome (XY), while females have two X chromosomes (XX).

2. **Gamete Formation**: During the formation of gametes (sperm and egg), males produce sperm that can carry either an X chromosome or a Y chromosome. Females produce eggs that always carry an X chromosome.

3. **Fertilization Process**: When fertilization occurs, the sperm (which can be either X or Y) fertilizes the egg (which is always X).

4. **Determining the Child's Sex**:
- If a sperm carrying an X chromosome fertilizes the egg, the resulting genotype will be XX, resulting in a female child.
- If a sperm carrying a Y chromosome fertilizes the egg, the resulting genotype will be XY, resulting in a male child.

5. **Conclusion**: The sex of the child is determined at the time of fertilization based on the type of sperm (X or Y) that fertilizes the egg. Therefore, the correct answer is that the sex of the child is determined at the time of fertilization on the basis of the kind of sperm.

### Final Answer
The sex of the child is determined at the time of fertilization on the basis of the kind of sperm.

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