OK, which of you kaiju moms claims this kid?

I just ordered a DVD of the 1968 kaiju eiga (monster movie) classic "Kaiju Soshingeki (Destroy All Monsters)" from Amazon.com.
Arguably the greatest of all kaiju eiga, "Kaiju Soshingeki" features all of the classic kaiju -- Godzilla, Rodan, Mothra (in caterpillar form), three-headed King Ghidorah and even Minya, the son of Godzilla.
For all of you breathlessly awaiting a plot synopsis, it goes something like this:
Aliens manipulate all of the world's monsters, causing them to attack Earth's major cities. Godzilla leads the monsters in an uprising against the aliens' top monster (the aforementioned King Ghidorah) and all ends happily ever after.
I was explaining this to Kerstin and Annika just now, and they marveled at the fact that Godzilla has a son.
"Who is the mom?" Annika asked.
Good question.
Whenever I watched "Destroy All Monsters" as a kid, I was always hopelessly feverish with an ear infection. I never did figure out the mother of the son of Godzilla.
I am hoping that question is finally answered when the DVD arrives from Amazon.com.