Is it the Jews that consider the foreskin a source of sexual disease, or is that just modern medicine? I know it symbolised uncleanliness in the bible, but didn't realise Jews had already linked it to diseases (I thought Jews practiced more for religious reasons than health).
But they do see it as a symbol of a new beginning, no? Entering into a covenant with God, getting rid of (or putting to death) the unclean that hinders? Being born again likewise involves entering into a covenant with God, the old self dying and receiving a new heart from God. So even if the Jews won't recognise it, I think the similarities are easily seen by those who are not biased.