No, as God created them... Your belly button comes from the umbilical cord... Because your belly-button (navel), or tummy-button as it's sometimes called, is a sign that you were once attached to your mother. You depended on that life-line — the umbilical cord — for your nourishment from her body as you developed inside her.Some food that is eaten and digested by the mother... But adam and eve were not born from a sperm fertilising the egg. God made them... Hence, no belly buttons... But once adam and eve have children, their children will have belly buttons.. Understand?

Adam and Eve were direct creations of God. They were not ever in a placenta or attached to a mother by umbilical cord, hence there certainly would not have been a reason for them to have them. Whether or not they did anyway, is impossible to know, of course, as no one else was around at the time. I'm going under 'no', they did not for biological reasons. No umbilical, no belly button.

Of course not they never existed unless you believe eve was created from one of Adams ribs that is,

Long live Darwin

no and if we ever find the bodies, adam should be missing a rib.

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but we won't find the bodies.

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because they are both fiction.