I have not seen proof that it is contagious. There are some out there who 'believe' it could be because there are couples that have UC and a test done on mice (how many tests have been done????), but I think that is just coincidence, just like two type 1 diabetics getting together or two people with cancer getting together.
My mother had UC my father never had it (they got married over 35 years ago)
My friends father has UC her mom never got it (married over 40 years ago)
My husband does not have UC and we have been together over 8 years
I want to see proof not hypothesis.