We must support families who have children or adult family members with disabilities. We must encourage an interpretation of halacha that emphasizes the notion that every person is a precious child of God, not to be thrown away or ignored due to limitations beyond their control. I believe that we are all unique gifts of God. This is not to say that every parent is capable of dealing with a disabled kid, clearly, some are not psychologically strong enough. I know that this is what everybody secretly thinks or wonders.
Nobody has the guts to say it outloud.
Those who wish to rear a child as a Jew and a Christian will not have our cooperation. They can try it without us. Rabbi Forstein is stating the position of the Reform movement, which is that a child of an interfaith relationship is considered Jewish if and only if it has a continuing positive relationship with Judaism as evidenced by acts associating it with the Jewish community. I hope this explanation helps. Those of us interested in gender equity find that if one religion is chosen over another, it is often because one spouse was dominant over the other.