Don't forget Thor and his goats. Not fiery or stormy or whathaveyou, just goats.
Or jolly St. Nick and his reindeer.
Also Poseidon was said to have invented horses for no other reason than to prove he could be as creative with making a land animal as he was with sea creatures.
Hey, my point was that maladapted pairings wouldn't be good for DF, not that they didn't exist.
Although I do have to say that (the various incarnations of) Santa's reindeer were very likely perfectly normal, land-bound reindeer at first, until somebody said, "Oh hey, you know what would be even cooler? They should totally be able to fly." And that story about Poseidon creating horses is pretty plausible, actually--just don't put any normal horses at the bottom of the sea. (Fun Fact: Horses are actually fairly good swimmers. You wouldn't think so, what with those skinny legs that don't look like they could push much water.)
And I don't think that spheres can truly render each other nonsensical. Even pregnancy & virginity, which you pointed out, don't render each other meaningless. One ends the other, yes, but they don't cancel for the same reason death and life don't cancel.
I can see a god of the "Life Force" bestowing Birth (or Rebirth) with one hand and dealing Death with the other (and perhaps animating Undeath with its
third hand?), particularly because most animals, in order to prolong their own Life, must inflict Death upon something else.
I can see a god of Daily Cycles, whose hair changes from black to blonde and back depending on the time of day.
But barring the extremely rare case of non-penetrative conception (and fat chance Toady is ever going to code sexual specifics
that detailed into the game), virginity and pregnancy are 100% mutually exclusive. The two can
never coexist in the same body. While Day/Night is clearly a cycle, and Life/Death can be viewed as one, the change from Virginity to Pregnancy is strictly one-way & irreversible. Now, it's true that every (successful) pregnancy results in the birth of a new
virgin, and therefore perpetuates the "cycle" of virginity . . . but by that exact same logic, the deity should be a goddess of "Pregnancy and Armpits", because every newborn baby has armpits. The pregnancy/virginity pairing is also not a cycle due to the fact that the
vast majority of virgins (unmarried females and all males) never become pregnant.
They might belong to a god presiding over children growing and becoming adults, perhaps. Both halves are there, and both would be needed for the god to perform their duty.
Both virginity and pregnancy do have direct ties to the sphere of Youth, yes, but from
opposite directions. The goddess cannot be both mother and daughter to
herself. (Unless you want to show her umbilical cord running from her navel into her own vagina--again, good luck getting that past Toady). It just makes a far neater arrangement to align virginity with a Youth deity, and pregnancy with a separate Mother goddess.
Heck, virginity being a primarily female thing is a rather strange link even in our culture.
It's based on the old "females as chattel" traditions. A family would get a much better price for a daughter if they could assure she was a virgin because A) her husband wouldn't be catching any STDs from her, and B) any kids that she squeezed out were assured to be his (provided that he himself would be similarly controlling after the wedding, of course). Young males, on the other hand, were allowed--even
expected--to screw around, because obviously they wouldn't be popping out kids, and who cares if they infect a few worthless females with syphilis. So pretty much every patriarchal culture become obsessed with preserving their daughters' virginity, and celebrating their sons' promiscuity.
But, as said,
none of that is reflected in DF. What with the game's
zero instances of sex outside wedlock (in the current version, at least), and marrying for life, then the two sexes are absolutely equal in this regard, and every marriage is between two virgins. So while virginity is very closely tied to femininity in RL, in DF it's purely genderless.
The population is not divided by gender, instead they are simply divided into the pregnancy-prone and the non-pregnancy-prone populations. Female virgins are classified as part of the second category, so effectively they are lumped in with the men.
My 2 cents: I would consider actively married
males to be "pregnancy-prone" in the sense that they contribute to your fort's population. If you've got a married man with good stats & attributes that you would like to see propagated in future generations, you get that guy OUT of the military, whether he's got a baby clinging to him or not. While I still consider pregnancy itself an overwhelmingly feminine condition, and any deity of pregnancy would have to be portrayed as female (barring seahorses as the exception), the social/military dynamics of DF do demand at least this token acknowledgement of the male.