Final answer:
Chlamydia infection is the leading cause of preventable infertility.
Step-by-step explanation:
The leading cause of preventable infertility is chlamydia infection. Chlamydia is a common sexually transmitted infection caused by the bacterium Chlamydia trachomatis. If left untreated, chlamydia can lead to pelvic inflammatory disease (PID), which can cause infertility in both men and women. In women, untreated chlamydia can cause scarring of the fallopian tubes, blocking the pathway for the egg to reach the uterus and increasing the risk of ectopic pregnancy.
Learn more about Causes of preventable infertility