What is the Halacha regarding a ten-year-old boy and mixed swimming? May he?
This is in a small private pool.
My impression is that this is a matter of halachic value, but there are differing community standards and guidelines on this kind of thing. (Well someone in the last decade or so has probably tried to make a one-size-fits-all law about this, but I'm not aware of it in classical sources.)
I'm told that the German Jewish community of Washington Heights draws its line for mixed swimming for boys of age nine. (Not unreasonable if you have to draw the line somewhere, in my humble opinion; and we do find classical sources discussing the age of nine for boys in other contexts -- e.g. Rambam Laws of Prohibited Relations 1:13.) It wouldn't surprise me if others were lenient with age 10,11, maybe even 12.
the age of chinuch starts at age three for certain things and age 5 for others. in regards to tznius chinuch starts at age 5. educating children on how they should behave and how to fulfill mitzvahs is important. chinuch cannot wait till bar mitzvah. if behavior patterns are not established early on then starting at the age of bar mitzvah won't be successful. "...it an absolute duty for every person to spend a half hour every day thinking about the Torah-education of children, and to do everything in his power - and beyond his power - to inspire children to follow the path along which they are being guided." (hayom yom) mixed swimming shouldn't be encouraged at any age because of the value of chinuch but certainly should discontinue by age 5