Did Adam and Eve have navels is a silly question. They didn’t, for several reasons:
1) Adam was fashioned out of earth, not in a womb, with an umbilical cord. And Eve was fashioned out of Adam’s rib.
2) We think they had navels because in all the paintings of Eden and the first family, Adam and Eve are shown with navels, probably because the models being used for those paintings had navels.
3) Adam and Eve never existed. It’s a folk-tale.
But this navel question has troubled theologians forever, because each question comes value-packed with a bunch of other questions, too.
Question: When Adam was formed from the dust of the ground — how old was he? I mean, yes, sure, technically he was 1 day old. But did God create an infant? Did God create a young man?
Question: If God created Adam as an adult, what memories would he have? Does he have memories? Did Adam and Eve dream at all? That first night’s first sleep — what was that like?
(There’s a midrash about Cain’s offering of the first of the field to God — that Cain, hearing of his parent’s banishment from the Garden, to which they could never return, and which they ached for daily, planted a new Garden, one that he knew would not be perfect, but would maybe be perfect enough. And its the fruits of this harvest that Cain brings to God, and which God rejects, for reasons that are only knowable to God.)
An Even Better Question: Why a penis? Why a vagina? Were the first humans supposed to be procreative? Or did God just have this Peaceable Kingdom in mind with only these exhibits? Adam and Eve never get a chance to have sex, let alone get Eve pregnant, before the Fall. And after the Fall, God’s punishment for Eve is pain in childbirth. How was childbirth expected to happen in the Garden of Eden? Does God decide that making humans is something he’s not good at, so he leaves it to us? Are we any better at making humans?
There are two creation stories in Genesis. Biblical literalists will say that there is only one, told from two points of view, and it would do none of us any good to try to convince them otherwise. But there are two creation stories that don’t entirely line up.
Genesis 1 was written at some point after Genesis 2. Genesis 1 is more liturgical in its tone, with its measured refrain. Genesis 2 is a folktale that was likely already fairly old when it was written down. The Bible — both the Hebrew and Christian texts — didn’t come to us from God in the order that we have it. (And it didn’t come to us from God anyway, but you get what I’m saying.) The Bible that we have now is a political document edited together to make a certain point. (Or, actually, points.)
Interestingly, Genesis 1 and Genesis 2 may not even necessarily be about the same God. When God is written about in Genesis 1, the word used for God is “ʼĕlôhîym” or, less complicatedly, elohim (אֱלֹהִים). Elohim usually refers to the Jewish god, but at other times in the Bible it refers to plural deities. This in itself is interesting because it points us in the direction of a sophisticated way of conceptualizing the divine: it suggests polytheism, because ʼĕlôhîym is plural, in a monotheistic culture/deity: Our God is All gods.
The God of Genesis 2 is referred to as YHWH ʼĕlôhîym. YHWH is also known as the Tetragrammaton. It is believed to be the actual name of God, and is never pronounced out loud. Also, we really can’t pronounce it out loud because Hebrew has consonants but no vowels. The best guess is Yahweh. However, you may notice in your Bible, if you’re a Bible reader, that sometimes the word LORD shows up in all-caps. That’s where the Tetragrammaton appears in the original Hebrew. When Jews are reading their Torah portions in synagogue, they won’t say Yahweh, or spell out Y, H, W, H. Instead they may say “Adonai,” or “HaShem,” or “hakadosh baruch hu” which translates to “The Holy One, Blessed Be He.”)
(Names are a powerful component of magic. Knowing something’s name gives you certain powers over it. If anyone knew and could utter the actual living name of God, it’s not clear entirely what would happen, but it would probably not be good.)
So, we have this majestic opening account, where creation is ordered and systematic. First this, and it was good, then this, and it was good. Actually, in Genesis 1, there are three places where the Bible doesn’t close with “and it was good”:
1) On the first day (Gen 1:3-5), when God separates the light from the darkness, that doesn’t get a corresponding “and it was good.” “it was good” for separating. (Separating isn’t creative, it’s ordering. As Sister Aloysius says in ::Doubt::, “When you take a step to address wrongdoing, you are taking a step away from God, but in His service.”)
2) On the second day, God separates waters from waters, and this is also not labeled as “good.” Here, we get a perfunctory “it was so.”
3) On the sixth day God creates humans, separated into male and female. The humans are blessed (Gen 1:28) — but that’s not the same as being called “good,” is it? Because God sees that “the wildlife of the earth after their kind, and the herd-animals after their kind, and all crawling things of the soil after their kind” were good (Gen 1:25); but humans, though, are not singled out for goodness, only a blessing. Their lives are about to become impossibly hard, with a final separation of human from garden.
In Genesis 2, though, we get the Creation Story as if it were a folktale. And we get some initial challenges to God’s omniscience — a concept that has been read ::into:: the Bible, but is not necessarily verified by the text of the Bible.
After God creates Adam — without a belly-button because Adam has no need of a belly-button — he notices that Adam seems lonely. So God says, “I’ll make a helpmate for Adam.” And he creates animals. And in the story, God proudly presents Adam with a new creature and sort of nods expectantly, like, “Huh? Right? Isn’t this what you’ve been missing?” And Adam, who is very polite, greets each creature with platonic love, names it, and then sort of shrugs sadly at God because while this rhinoceros is very cool, as was the peacock before it and the nudibranch that needed to ::immediately:: be put into water, none of these are helpmates. Put more coarsely: he can’t fuck these animals. He can’t talk to them, tell them about his day (which started literally 15 minutes earlier), sleep cradled together like commas. And then, finally, God says, “Well, let’s try this.” And from Adam’s rib, he makes an Eve.
(Or he makes Lilith, but not out of a rib, and this is from a later tradition than the Garden story. Once upon a time, God created Adam and Lilith, both out of the dust of the ground. Lilith refused to be subservient to Adam, which, good for her; but, however, she’s banished and becomes a demon and/or fucks the archangel Samael, who will later wrestle with Jacob, only I don’t think that happened, I think Jacob actually wrestles with Esau, and we’ll talk about that another time when I feel like it.)
God breaths the Breath of Life — or a soul — into Adam. We don’t know if God breathed a soul into Eve or not. The Bible doesn’t say. She has an innate curiosity and confidence that Adam doesn’t appear to have. The Gnostics revered her as the champion of Wisdom and Knowledge. Christians have used her to blame women for everything forever.

(A final bit of trivia, on the subject of navels: When God is haranguing Job for daring to ask “why?”, God says, “Behold now behemoth, which I made with thee; he eateth grass as an ox. Lo now, his strength is in his loins, and his force is in the navel of his belly.”)