In reply to:

The Candiru!


I have heard of this-- it lives off nitrogen--(which is why it normal lives in the gills of other fish) and it can sense a strong source of nitrogen in water, and swims upstream to the source--

It seems if there is a flow of urine, the urethra is wide enough for it to swim in. (but it can't swim up a stream out of the water-- so you can stand on a dock, or boat deck) So it could happen– but I guess it didn't happen very often (still who wants to take that kind of a chance?)

and yes, i am sure women would be more vulnerable-- but it might actually enter their bladder since there urethra is so short--