Explaining the Virgin Birth...

The virgin birth is undoubtedly a difficult topic for children to grasp and even more difficult for parents to comfortably explain. This part of the Christmas story is one that parents sometimes feel trapped with because it is a crucial part of the story of Jesus' birth and one that shouldn't be overlooked or underappreciated, but explaining virginity to a young child is a conversation most prefer not to have. Jesus was sent to us in the purest form and there is a deep meaning behind this Immaculate Conception. Jesus was fully human and fully God. There is no other like him. But how do we explain this immense imagery that God portrayed through Jesus' birth, to children? 

Here is an article on a couple different ways to phrase the virgin birth to children. The article also includes a link to a YouTube video that does a great job of using "kid terms" in the first 60 seconds. You'll notice, there is not a lot of agreement on the best phrasing. 
A great way it is phrased is to say, "It takes a mommy and a daddy to make a baby. But for Jesus it was different, it was just Mary, and after Jesus was born, Mary and Joseph got married. Jesus was different than any other baby because he was God's son." 

The Virgin Birth and Kids