Which of the following statements about Nonoxynol-9 is true?

• A. It is a barrier method
• B. It is an antibiotic
• C. It is a hormone
• D. It is a spermicide

Answer: (D)

Nonoxynol-9 is a spermicide, a chemical that disrupts sperm membranes to reduce sperm motility and viability, thereby preventing fertilization. It functions as a chemical agent inserted in the vagina (as gels, foams, or suppositories) and can be used with condoms or alone. It is not a barrier method, which refers to physical obstacles like condoms or diaphragms. It is not an antibiotic, since it does not kill or inhibit pathogens in infections. It is not a hormone, as it does not affect the endocrine system or hormone levels. While spermicides can help prevent pregnancy, they are generally less effective than other methods and can cause vaginal irritation with frequent use.