Where did stds come from? [READ DETAILS BEFORE ANSWERING]?

I know if 2 people are negative for stds and have sex (assuming they only have sex with each other) they can t create stds. Then where did STDs come from then?

Where did the first chicken come from if there wasn't an egg that a previous chicken laid?

Life evolved on earth from the evolution of a single cell into a complex organism called a human. At the same time that everything was at the cellular level were the other organisms that evolved in parallel to man. STD's came from our evolutionary history that goes back to the primordial soup.

STD's are transmitted and not created or made. One person must have contracted the STD from another and they in turn then transmit it to somebody else. Neither of them created it.

In theory, a group of lets say 8 people can all have sex with each other and as long as they are all std-free no stds would be created?

If none of them have an STD then they can not transmit an STD. Again no one can create an STD. It is also hard to detect whether or not one really doesn't have an STD as some do not have symptoms or testing can be inaccurate.

Is it because one gave oral while having a cold sore or what?

Having oral sex can transmit sexually transmitted diseases yes.

Also, it s fine to have unprotected sex if both don t have stds right? For straight (assuming they re ok with getting prego), gay, and lesbian couples?

Any unprotected sex carries risk because people lie or don't really know whether or not they truly have an STD. Testing isn't always accurate or sometime not practical for every STD or STI out there.

That's a lengthy study in evolutionary biology. Basically, some little bastard organism mutates and that mutation turns out to make it well suited for living [in this case] in someone's junk. Yada yada yada... It burns when you pee.