Identify the incorrect statements for sex-determination in humans.

Options

A. Humans contain 23 pairs of autosomes.
B. Females produce only one type of ovum.
C. Genetic makeup of sperm determines the sex of the child.
D. In males, two types of gametes are produced.

Answer

To solve the question of identifying the incorrect statements regarding sex determination in humans, we can break down the information as follows:

### Step-by-Step Solution:

1. **Understanding Chromosome Composition**:
- Humans have a total of 46 chromosomes, which are organized into 23 pairs. Out of these, 22 pairs are autosomes, and 1 pair consists of sex chromosomes (XX for females and XY for males).

**Hint**: Remember that autosomes are non-sex chromosomes, while sex chromosomes determine the sex of an individual.

2. **Evaluating Statement A**:
- The first statement claims that humans contain 23 pairs of autosomes. This is incorrect because, as established, there are only 22 pairs of autosomes and 1 pair of sex chromosomes.

**Hint**: Count the types of chromosomes carefully; differentiate between autosomes and sex chromosomes.

3. **Evaluating Statement B**:
- The second statement states that females produce only one type of ovum. This is correct because all ova produced by females carry the X chromosome.

**Hint**: Consider the genetic contribution of females to offspring.

4. **Evaluating Statement C**:
- The third statement mentions that the genetic makeup of the sperm determines the sex of a child. This is correct because sperm can carry either an X or a Y chromosome, which will determine whether the child is male (XY) or female (XX).

**Hint**: Think about how the combination of chromosomes from both parents determines the sex of the child.

5. **Evaluating Statement D**:
- The fourth statement indicates that in males, two types of gametes are produced. This is also correct, as males produce sperm that can either carry an X chromosome or a Y chromosome.

**Hint**: Recall the process of gamete formation in males and the types of chromosomes involved.

### Conclusion:
The incorrect statement regarding sex determination in humans is **Statement A**, which incorrectly states that humans contain 23 pairs of autosomes.