Final answer:
Chlamydia is a bacterial STI that can cause infertility in both men and women.
Step-by-step explanation:
Chlamydia is a bacterial sexually transmitted infection (STI) that usually affects mucous membranes and can cause infertility. It is caused by the bacterium Chlamydia trachomatis. In women, chlamydia can infect the cervix and sometimes the urethra, leading to symptoms such as vaginal or urethral discharge, bleeding, and painful urination. If left untreated, the infection can spread to the upper reproductive tract, causing pelvic inflammatory disease (PID) and increasing the risk of ectopic pregnancy and infertility.