Don't Ignore the Symptoms: Sexual Problems, STDs Affect Millions

Video: The Straight Talk on Herpes

3. Genital Human Papillomavirus. It's a common complaint but should not be taken lightly: Although 90 percent of cases will be resolved by a person's own immune system within two years, some of the 40-plus HPV strains that infect the genitals boost the risk of certain cancers, according to the CDC. Cervical cancer, for one, can be especially dangerous because it tends not to produce symptoms until it's quite advanced. More rarely, HPV infections can lead to vulvar, vaginal, anal, or penile cancer. Since the infection is caused by a virus, there is no treatment (although warts can be removed by medications or physicians). Regular Pap tests and exams are recommended to flag signs of cancer before it can develop. Gardasil, a vaccine that can protect women against some of the strains linked to cervical cancer, is recommended for some women.

4. Gonorrhea. Like chlamydia, this common bacterial STD can progress silently, leaving people with intractable health problems. Symptoms such as discolored penile discharge or signs that mimic those of a bladder or vaginal infection may occur. Unnoticed and untreated, gonorrhea can cause infertility in both men and women. It is also a common culprit behind pelvic inflammatory disease. Once treated with antibiotics, people can be re-infected by untreated partners.

5. Pelvic Inflammatory Disease. Pelvic inflammatory disease occurs when the uterus, fallopian tubes, or other female reproductive organs become invaded by infection-causing bacteria. Two common culprits are chlamydia and gonorrhea. Each year, more than 100,000 women are left infertile by an untreated case of PID, which can be cured with antibiotics, according to the CDC. PID can lead to lifelong pelvic pain and pus-filled internal abscesses and can raise the odds of ectopic pregnancies. Suspicious vaginal discharge, painful sex or urination, and bleeding between periods may all be signs that something is awry.

6. Trichomoniasis. A one-celled parasite causes this STD, and a frothy, odorous, greenish-yellow discharge can be a sign that a woman has it. Infected men don't usually show signs, though some may experience abnormal penile discharge or pain after urinating or ejaculating. Trichomoniasis can make women more likely to contract HIV if exposed and may increase the likelihood that an HIV-infected woman will transmit HIV to her partner. Trichomoniasis is curable with medications.