KaitoDies said: I really don't want to know the explanation of why there is blood on her thighs.
Actually, it scares me how I got the reference for that before even checking on the source to verify it. Thus added tags.
In Parasyte (Kiseijuu),... a parasite tunes perfectly to the first host it infects. If it latches to another new body, it might have trouble adapting to it if it has a different body structure. For instance, gender difference.