Sometimes the Churches tendency to Focus on the Family bring in sharp contrast all the non-traditional non-nuclear families: widows & widowers, orphans being raised by the system / state, single mothers, single fathers, older teenagers who take care of their younger siblings, step-families, happily single men and women, complicated and extended dating relationships, believers and non-believers etc.
By saying 'Family is the foundation of Christianity, God wants us to know Him as Father and Son." You're leaving out the Holy Spirit aspect of God, where exactly does He fit in this family? Uncle? Brother? Cousin? Nephew? Are you saying that by the virtue of being the Son's mother, Mary fills the role of the Father's wife? That just doesn't make any sense.
Woman does not possess the image of God in herself but only when taken together
with the male who is her head, so that the whole substance is one image. But
when she is assigned the role as helpmate, a function that pertains to her
alone, then she is not the image of God. But as far as the man is concerned, he
is by himself alone the image of God just as fully and completely as when he and
the woman are joined together into one. –Saint Augustine, Bishop of Hippo Regius (354-430)
The church fathers were products of a time when it was considered a fact of life that women were second-class, barely above the status of slaves if they were free, below the status of men if they were slaves. They couldn't conceive it possible for a woman to have a relationship with God outside of fulfilling the role of wife. In other words - unmarried women had no representation before God or hope of a relationship with God. Perhaps that school of thought exists in church today - which is why so many churches offer marriage prep for their single members.
But family is more complicated than the traditional nuclear family that seems to be worshipped and raised up as the standard of family by the church. Either one kind of family is 'right' and all other kinds are 'wrong' or Christianity has all sorts of 'wrong' ideas about what is 'right.'
Much of what I see about Christianity is the made-for-t.v. version, cleaned up, happy faces, polite words, etc. What I don't see is that which they hide well, statistics on all forms of abuse within the church, Christians living in constant fear of punishment for even the slightest offense, people being denied opportunity because the Bible doesn't say that they can do something, etc. ... basically using the Bible to justify accepting any attitude that would be unacceptable outside of Christianity as if it was approved by God, moral and righteous.