He wonders what it will look like. It's only a collection of cells inside her the first time they learned of its existence, garnering nutrition from his daily pecks on her forehead as he rolls over in the morning, growing despite the cold undercurrent between them, the absence of understanding he sometimes feels, making him shiver against her body. But they've created this together, a little one of 'them', splitting and replicating systematically without being told.
A few surges of excited anxiety overwhelm him at random; wants to ask her if she feels the same way, if having their child so close but unable to see it guides knives through her chest as well. He can't say that he's already attached and doesn't recognize that she feels the same way until tears pour when she first holds Yamato, when nothing exists but Yamato and his tiny sighs as he naps. Hiroaki's tongue is glued down, thinking that he should have known that Yamato would have Natsuko's blond hair of summer and enough blue to tie a poignant knot in his throat.
When Takeru is only a word on Natsuko's lips, Hiroaki again wonders what this baby will look like. But Takeru looks like Yamato, because that's who Yamato seems to love the most once Takeru's giggles fill their lives. And Yamato looks like Natsuko because that's who Hiroaki loves the most, without remorse, without hesitation, without logic or fear. Hiroaki should have known. Of course that's what their children look like.