The traditional family is under assault these days. Watch a primetime television program about the family and you'll soon discover that fathers are presented as idiotic, mothers as overbearing, and children as wise beyond their years. That's assuming you can find a program portraying a "traditional" family with a husband and a wife.
To say "traditional" families are under attack, however, is to acknowledge that our definition of the family is more culturally informed than biblically informed. Our Western, modern model of the family, where a husband and wife live together and rear two or three children, is not the model we see in the Bible, where husbands were often married to multiple wives, had relationships with concubines, and produced a prodigious number of children. Defining family, therefore, especially a "biblical" or "Christian" family, is no easy task. Frankly, it's probably easier to bag an octopus than to define a "biblical family."
What we can definitively say is this: God is the originator of the family and continues to hold the patent. The ideal, established at the beginning of humanity, is for one man and one woman to join in a spiritually and physically committed union for a lifetime, conceiving and rearing children (Genesis 1:27–28; 2:18, 21–25). Clearly, this model wasn't followed consistently throughout the Scriptures and is not followed today, where single parents, married couples without children, grandparents rearing their grandchildren, and empty-nesters—just to mention a few—make up a considerable percentage of "Christian" families. We would be hard-pressed not to label these relationships "families," even though they don't meet the ideal set forth in Genesis. Furthermore, the Lord continues to bless these types of families.
So where does this leave us in trying to define family from a Christian perspective? We can affirm at least this much: "A Christian family is a group of people who are related to each other through marriage, birth, or adoption and are committed, first and foremost, to the person and work of Jesus Christ, faithfully witnessing to the love, power, and forgiveness of God to a watching world in its unique time and place."