Hi Paul,
Amongst the Ultra Orthodox here in Israel, their young men fully and completely keep themselves virgins until marriage, (as do their young ladies). I am convinced the 144,000 will come out of the huge Ultra Orthodox community in Jerusalem. It is known there are already a growing number of them that believe that Yeshua is the awaited Messiah. A brother in the Messiah, who is an evangelist told me a while back an Ultra Orthodox man knocked on his door, and told him: "I believe like you do", and then turned and left, leaving my brother in Messiah with his jaw on the door step.
Blessings!
JDS