No idea, though I think there's a tiemcock tag, so you ought to be able to find it that way... And I don't blame you for being afraid to google it!

:At least in its lesser form of "Why would the doctor fancy junior members of an alien species?"

Quite. Especially the idea that Rose/ Doctor is the Greatest Love of All Time. It's only believable at all as his not-very-edifying-if-you-stop-and-think midlife crisis... I get slightly queasy about (putative; I don't know what exactly we're supposed to make of Ten/ Rose, but I'm not convinced they're lovers) relationships that are so wildly imbalanced.

It's probably Sayers' fault :)