Is your religion OK w/ allowing gays to be 2nd cl citizens and have civil unions but not marriage?

why can't gay people accept civil unions instead of redefining marriage...the institute of marriage, man and woman, will survive without the state propping it up...can the same be said for "gay" marriage...when you redefine marriage you are also redefining fatherhood and motherhood...you are also creating equal rights to the children of those "marriages" the biology of humans no longer matters...if that is the case what determines parenthood in the eyes of the law...your simplistic view is said...i wish you were open minded...