Blue, that's disgusting. Just, eww.
Well, maybe we can approach this by asking about non-removable prosthetics. Things like pacemakers, cochlear implants, titanium pins, and so on. Prosthetics are really common these days. I myself have eight hard plastic patches glued to my teeth to protect my molars.
Prosthetics are mentioned twice in canon:
- Andalite translator-chips. Apparently, there's no problem morphing with these--since every Andalite in the series who can morph has one of these. Even very small morphs: flea, mosquito.
- The Yeerk shark-control chips. Apparently, there is a problem morphing with these.
The first point makes sense. The Andalite military isn't going to be happy with a morphing tech that is incompatible with their translators. This also offers a theoretical basis for morphing clothing. Morphing can trap inanimate matter that's inside the body, or apparently, close to the body. But, it's clearly not perfect. When the story requires, morphing a small animal will free you of Evil Alien Mind Control Technology
(TM).
So, where does that put us with vivipary? If Andalites are viviparous, I wouldn't expect morphing while pregnant to be a problem. If not? Who knows?
Oh, a bit of a pet peeve of mine: DNA. How do we know that morphing is DNA based?
- Elfangor's Cliff-Notes-description of morphing. He was describing the technology to aliens and really only paying attention to how to use it--not how it works. We shouldn't take this as a technical specification.
- The Animorphs' narrative musings. They learned everything they know from Elfangor. See previous point.
- Ax doesn't correct them. But, Ax was at best an average student, and he was never training to be a military-scientist, anyway.
Well, that's not the worst evidence I've ever seen. However, DNA does not encode everything that morphing duplicates--such as age. So, can we please, please stop assuming that morphing only copies DNA?
[spoiler="extremely geeky tangent"]Especially because it is entirely possible for one organism to have multiple DNA sequences. This is rare among terrestrial species--but when it does occur, such an individual, a tetragametic chimera, almost always appears normal--so that exact rates of chimerism are not known. It's only under unusual circumstances that the condition is detected, like a
woman apparently conceiving some other woman's children. There's no reason to not think that in some alien species, chimerism is normal. For example, the
Mgalekgolo in the Halo canon.[/spoiler]