[XBob]

I forgot to put in symbiotic - so it could be a symbiotic parasite.

[hocndoc]

There's no such thing as a symbiotic parasite, which is an oxymoron.
An embryo is functioning as a whole in an organized manner to sustain its life and development, exactly as it should. The embryos of mammals are not parasites (parasites can't be members of the same species) and they are not a part of their mothers. They are within their mothers and the pregnancy is mutually beneficial in the normal course, so the mother and the child are symbiotes.