Not saying its the issue here, but quite often women's health is impacted by the men they live with and / or have sex with.
eg in the days when printing was more common, wives of men who worked as printers had a higher instance of cervical cancer.
This was assumed to be that if men washed their hands at all, it would be after they had unrinated.
There probably were and probably still are many jobs that involve liquids, chemicals or whatever, so that men doing this work should to told to always wash their hand before handling their penis.
And on reflection women doing this work, as unless you are using a whole toilet roll, if your hands still have traces of something poisonous to the body you dont want to accidently smear it on your self.
Sorry - a bit off topic, unless it is known that mouth ulcers can be caused by something unintentionally being ingested.