How do people get STDs?

gloveSTDs are normally transmitted through sexual contact in one of two ways:

1. Exposure to infected semen, vaginal fluid or blood:

  • Viruses or bacteria in these fluids enter the body through mucosal membranes in the female’s vagina or cervix and the male’s urethra.
  • Examples include HIV, Hepatitis B & C, Gonorrhea, Chlamydia and Trichomoniasis.

2. Contact with infected skin in genital areas:

  • Genital areas include the penis, vagina, pubic area, inner thighs or anus.
  • A person can be contagious even when no visible symptoms are present.  In fact, most people develop no symptoms for a period of time and do not realize they are infected.
  • Infection may result in outbreaks of ulcers (syphilis, chancroid), small red bumps (scabies), blisters (genital herpes) or warts (HPV).
  • Intercourse is not necessary to transmit these infections.  They can spread simply through skin-to-skin contact in infected areas.

It is also possible to transmit some STDs without sexual contact.  For example, sharing needles is extremely dangerous because it can result in injecting another person’s infected blood particles into your own bloodstream.

Here are some frequently asked questions about STD infection:

Can I get STDs from oral sex?

Yes.  Almost all STDs can be transmitted through oral sex.  To see a few examples, click here.

Can I get STDs from kissing?

“This is possible but not very common. If your partner’s mouth is infected with an STD, then he or she may be able to pass that infection to your mouth during a kiss. Cold sores (oral herpes) can be passed through a kiss if your partner is infected. If your partner has an infection in his or her genital area, then kissing on the mouth will not transmit the infection, and blood-borne infections like HIV or Hepatitis B or C can only be passed through kissing if there is the exchange of infected blood.”1

Can I get STDs from a toilet seat?

ben_stillerIn the movie Along Came Polly, character Reuben Feffer (Ben Stiller) picked up an STD from a toilet seat.  Hollywood hype or the real deal?

Answer:  Infection is highly unlikely because the micro-organisms that cause STDs can’t survive outside of the human body for very long.  In most cases infection would require a woman’s vagina or a man’s urethra to have direct contact with fresh genital secretions or blood on the toilet seat.  Parasites probably have the best chance of infecting someone via contact with a toilet seat.  For example, pubic lice can survive for up to 24 hours outside the body, and can even spread through contact with an infected person’s clothes, towels, or bed linens.2

Can babies get STDs from their moms?

Yes.  Babies can get STDs from their moms before, during or after birth:3

  • Syphilis and HIV can infect a baby inside a mother’s womb.
  • Gonorrhea, chlamydia and genital herpes can infect a baby as it passes through the birth canal.
  • HIV can infect babies through breastfeeding.

The harmful effects to babies vary.  Some children are born dead (stillbirth).  Others have complications ranging from eye infection, pneumonia, brain damage, blindness, liver damage, etc.

Doctors frequently perform a C-section (abdominal birth) if they believe there is any risk of a baby becoming infected during a normal, vaginal birth.


  1. American Social Health Association, “Frequently Asked Questions.”
  2. Ibid.
  3. Centers for Disease Control, “STDs and Pregnancy – CDC Fact Sheet.”