Why do parents love their kids ?

Its just an instinct. UNCONDITIONAL LOVE right term to define. i and my husband when our first yr of marriage we really don't have a plan to have a baby bcoz of other priorities and we think that we're not yet ready physically and financially. But when i knew that i was 3 months pregnant ohhhh the excitement we can't explain until the time i gave birth to my son. we our now complete as man and woman as family words are not enough to express how happy we are as parents the joy that our son brought to us. We want to give our son the love attention that we haven't experience when we are still kids im not saying that our parents don't love us its just we want to give our son the best not to spoiled him i mean right love, attention and even quality education.