Are you telling me that this isn't supposed to be a regular occurrence?
That's assuming 'other universes' that have counter parts etc actually exist and even then, that still doesn't change a fact that something being possible in that universe isn't in this one.
Take Red Dwarf for example. They go to alternate universe where all their counterparts are women (except Cat, whos counterpart is Dog). In that universe, it's men who get pregnant. That doesn't change the fact that in their own universe, that isn't a possibility.
It also doesn't change the fact that in this universe it isn't possible for a human born only with male sexual organs to naturally get pregnant either just because it is possible in an alternate universe of what is itself an alternate universe.
What you're essentially doing is using the "it happened 'because God'" argument. It's fine as a means of making sure you can't be proven wrong, but it doesn't make you right.