The growing size of the human population is a cause of concern for all people. The rate of birth and death in a given population will determine its size. Reproduction is the process by which organisms increase their population. The process of sexual maturation for reproduction is gradual and takes place while general body growth is still going on. Some degree of sexual maturation does not necessarily mean that the mind or body is ready for sexual acts or for having and bringing up children. Various contraceptive devices are being used by human beings to control the size of population.
What are common signs of sexual maturation in boys is:

Options

A. Broadening of shoulders
B. Development of mammary glands
C. Broadening of waist
D. High pitch of voice

Explanation

### Step-by-Step Solution:

1. **Understanding Sexual Maturation**: Sexual maturation is the process through which individuals develop the ability to reproduce. It involves physical, hormonal, and emotional changes that prepare the body for reproduction.

2. **Identifying the Age of Puberty**: For boys, puberty typically begins between the ages of 13 and 14. This is the time when significant changes occur in the body due to hormonal changes, primarily driven by testosterone.

3. **Recognizing the Role of Testosterone**: Testosterone is the primary male sex hormone responsible for the development of secondary sexual characteristics during puberty. It plays a crucial role in the physical changes that occur in boys.

4. **Common Signs of Sexual Maturation in Boys**:
- **Broadening of Shoulders**: One of the most noticeable changes during male puberty is the broadening of shoulders, which gives a more masculine physique.
- **Growth of Facial and Body Hair**: Boys will begin to grow hair on their face, underarms, and other parts of the body.
- **Deepening of Voice**: The voice box (larynx) grows, causing the voice to deepen.
- **Increased Muscle Mass**: Boys typically experience an increase in muscle mass and strength.
- **Development of Genitalia**: The penis and testicles grow in size, and boys may begin to experience erections and nocturnal emissions.

5. **Conclusion**: The common signs of sexual maturation in boys include the broadening of shoulders, growth of body hair, deepening of voice, increased muscle mass, and development of genitalia.