while not related to poly, more to lesbians & gays, ... but aside from that it's all the same issues.
a documentry film "for the bible told me so", they followed and talked with quite a few christian families and their strong views of what is and is not acceptable sexuality.
many came to accept that their children were still the same when they came out, it took those families a long time, coming from a christian background these families had to really sit down and re-examine their faith, at least re-examine what it meant, what it says is and isn't acceptable more than just how it's interpreted.
a few though unfortunatly never got to reach that point, as their children came out they were not accepted "oh it's just a phase", ... unfortunately for those families they'll never get to see their children again.
yes it's important for so many that the ones that accept them the most be their family, that's so very important for so many people, ... and when that acceptance does not come, they just can't handle it.
then it's doubly as hard on the parents when they realize fully how serious and important to their children it was to come out to them.