When you were born into a family love was automatic but in blended families people have to choose love. Stepparents choose to love children not their own. Stepsiblings call each other brother and sister. And stepchildren get to be adopted, so to speak by the stepparent's love. In Romans chapter 8 the Bible explains that God, our Heavenly Father, has adopted us into His family. He didn't have to but He did. Sounds to me like blended families get to be a living picture of God's choosing love.