Why does this happen?

[EliseZippy]

How is it that manual sex can cause an STI, but cannot cause a pregnancy? Also, is it possible to get an STI from touching dried pre-ejaculatory fluid/dried semen (that cannot pose a threat to causing a pregnancy) and then touching yourself before washing your hands? If so, why doesn't this cause a pregnancy as well?

Also, I started birth control this month, and is it possible for the sudden fluctuation of hormones to cause a UTI or yeast infection? And do you know if it is possible to get Pelvic Inflammatory Disease and yet not come into contact with semen or pre-ejaculatory fluid?

[Sam W]

Hi Elisezippy,

The short answer is that what sperm need to survive and do their job and what infections need to pass from person to person are different environments, and sperm are more fragile overall. And some STIs, like HPV, are passed via skin to skin contact rather than by fluids, which is why something like manual sex could pose a risk of them.

Birth control pills are one thing that can potentially cause a yeast infection, but by no means is that a guaranteed outcome. If you're having symptoms that are concerning you as being a UTI, yeast infection, or PID, then you'll want to check in with a healthcare provider to see what's up.

[Heather]

To be clear, PID occurs as a result of untreated genital or reproductive infections. So, as long as a person isn't walking around with undiagnosed and untreated infections, they are not going to wind up with PID.

[EliseZippy]

Thank you very much for the information and advice!