Indeed, until the late C19, when rubber condoms were introduced, condoms were leaky affairs, being made of either animal guts, or chamois leather, sewn up. Semen would leak through this, but bacteria were mush less likely to make the journey in the other direction!

Incidentally, on a note of social history, rubber condoms were, initially, used almost exclusively by the upper middle classes in England. Thye bacame more common for working class men during the First World War, when they were issued to the troops in Frnace when the went for R&R behind the lines. They were handed out in brown envelopes, and it is from this that the slang term for condoms, "French Letters" arose.

I'm immortal until proven otherwise