"That's a really interesting question Sue. I have noticed that both my sons (grown up now) use public toilets as little as possible, and my husband says that when he goes into a public toilet with them neither of them use the urinals. When they were at school they both refused to use the school toilets and we used to have to run home from school and clear a way through to the toilet because they were bursting to pee. I was sure they were unaware of my problems as they were growing up and hate to think that it might have been a behaviour they learned from me, but I'd be really interested in a professional view of paruresis as hereditary."
There was research reported on recently in the magazine Nature Neuroscience that seemed to show laboratory rats inheriting a specific fear. The parent rats were trained to fear the semell of a specific chemical. The pups were raised in the absebce of the parent, yet showed the same fear reaction. This trait showed in later generations as well. Dissection showed that there were differences in the neurons in the pups compared to a control group, and the relevant gene was different as well. The article can be found here:
This flies in the face of accepted genetics, but the research was apparently rigorous. Followiing normal scientific practice, research needs to be conducted by others to try to both replicate the results, and to try to disprove them. So early days.