Which statement about intracytoplasmic sperm injection (ICSI) is true?

• A. It bypasses natural fertilization without micromanipulation.
• B. It is used exclusively for cases of female-factor infertility.
• C. It eliminates the need for sperm retrieval in azoospermia.
• D. It involves injecting a single sperm directly into the oocyte to achieve fertilization.

Answer: (D)

Intracytoplasmic sperm injection relies on micromanipulation to inject a single sperm directly into the cytoplasm of an oocyte, enabling fertilization even when the sperm cannot penetrate the oocyte on its own. This direct injection bypasses the normal barriers a sperm must overcome, such as binding to and penetrating the zona pellucida and oolemma, which is why the technique is especially useful in cases of male-factor infertility or previous fertilization failures. A retrieval of viable sperm is still required if there is no ejaculated sperm, such as in azoospermia, so the method does not eliminate the need for sperm retrieval.

This approach is not exclusive to female-factor infertility; it’s employed for various infertility scenarios where fertilization is compromised. It also cannot be described as being performed without micromanipulation, which is fundamental to how ICSI works. Replacing natural fertilization with this targeted injection is the core idea behind the procedure, matching the statement that directly injecting a single sperm into the oocyte achieves fertilization.