Your mother and I take names seriously, and wanted to choose one for you that signified something important - a name that partly describes what we hope for you, but also one that is open enough for you to attach meaning to, and decide what it means for you to be a Thomas, a Nathanael, a Moothart. Names are funny like that - they both define us and are defined by us. Our culture has lost most of the importance attached to names, but you only need to turn to the Bible to see it - in Joshua, Isaiah, Abraham, Peter, Jesus.
Your are named primarily after the apostle Thomas and Philip's friend Nathanael. Both of them responded to Jesus with initially skeptical reactions, but (more importantly to your mother and I) both made great professions of faith when confronted by Him.
Nathanael's skepticism ("can anything good come out of Nazareth?") is overcome by Philip's invitation - "Come and see". And when he came and saw, he declared "Rabbi, you are the son of God! You are the kind of Israel!".
Thomas' skepticism of the resurrection ("unless I see...") is likewise overcome by Jesus, as he leaps ahead of the other disciples and declares Jesus to be not only Lord, but God. This confession hearkens all the way back to the prologue of John's gospel: Jesus is the Word, not only with God but also equal to God (1:1). And in the paradox of the trinity, Jesus who declares the unseen God to us (1:18) is himself God - the invisible Word made visible, touchable flesh.
You are also named after Thomas Aquinas. He lived during a time of real cultural, military, and intellectual challenge to Christianity from the Muslim world. Against the prominent Islamic scholars of the day, he argued that all truth is one, that two truths can't be at variance with each other. He also labored to place the newly-rediscovered works of Aristotle in a Christian context.
The third Thomas you are named after is my father. You have inherited his smile - use it wisely. With great power comes great responsibility. He's influenced who I am and how I parent in ways I don't know and am still discovering, but one of them is a desire to help you grow by not being overbearing and letting you make as many of your own decisions as possible. I want to give you the freedom to make mistakes on your own, to prayerfully decide how to grow into manhood without pressure from me to do or be anything specific to gain my approval. I want to provide guidance, advice, prayer, and help (and occasionally the rod - though less of that when you're older).
We don't know what kind of man you will become, but we are praying that in your journey you will confess the faith with the passion of the apostles, defend it with zeal, and face all of your labors with your grandpa's smile.