Okay it’s like 2 AM. But Percy and Annabeth struggle to have a baby for a long time. Mortal fertility doctors say there’s nothing wrong and so they know it’s the gods. More specifically, it’s Hera being a petty bitch. They make offerings to Demeter and Dionysus hoping that blessings from the other fertility gods will help offset Hera’s doings. Annabeth gets pregnant, but Hera is still the goddess of child birth, so she miscarries. After that they stop trying for awhile. It’s too painful. They focus on the demigod kids they foster instead.
After awhile, Annabeth gets pregnant again. They haven’t made any more offerings, but Percy wonders if Mr. D still remembers all that Diet Coke and gold. In any case, they’re holding their breath, making lots of offerings, including to Hera. They don’t tell anyone until it’s unavoidable because she’s showing. They don’t look at baby name books or have a baby shower or anything, too afraid of getting attached, of facing that loss and pain again.
But apparently Hera’s found her compassion, because Annabeth gives birth to a healthy baby girl—Annabeth’s spitting image, except for her sea green eyes and the freckles on her cheeks. She’s their little miracle, and the day she is born they burn so many offerings for Hera, it’s a little ridiculous. And some for Dionysus and Demeter, just to be safe.