Sarah Polley and Adrien Brody (the King and Queen of Quirk) play a pair of super-cool biochemists who are developing a new creature for a shady pharmaceutical corporation. When the company threatens to shut down their advances into human / animal splicing, they go off piste and inject a piece of human DNA into a mutant egg. Whose DNA it is will become highly significant as the scientists play out their own turbulent inner lives. Polley's character is the agent; Brody stands by and watches aghast.
From the off the creature is troublesome: it almost stabs Polley to death before it's even born. When it first appears it's a little, lizardy type thing, stumbling around like a weird sort of chicken. It eventually grows into a young woman of alien-like appearance. Polley and Brody must keep it - or rather her (and therein lies the rub) hidden. Thus arises the terrible question: is it just an experiment, or is it a person? They call her 'Dren' (NERD backwards)'; she is intelligent and emotional. They keep her in a basement (in a horrible parallel to Polley's character's own childhood; raised by a mad mother and kept in a bare room). They develop emotional attachments to Dren, which eventually cause enormous problems.
When one of the non-human creatures that the scientists created turns into a male, killing its rival in spectacular fashion in front of a whole room of potential investors, it soon seems that Dren may not be all that she seems, turning from lust object and surrogate child into the monster from Jeepers Creepers. The end of the film is a perfectly judged piece of horror. It also raises troubling questions about our prejudices, and our need to keep disabled and deformed people out of sight. Splice is an intelligent, keenly disturbing piece of science fiction which, I hope, will not see its real questions raised in the real world for a good long time yet...