This is a great start to what could become a first full novel for Ms. Crouthamel. While it needs help with sentence structure and grammar at times, the story keeps you turning the page and wondering what wonderful or terrible thing might happen next. I feel this novella as a great base to tweak and expand into a larger novel. I enjoyed the characters and situations they were put in; their histories were well thought out. Unwanted is from the mind of obviously a talented young writer who just needs some editing help.
As mentioned, there are some areas that could be expanded and edited differently. I have mentioned a few here to start.
I feel the evil doctor portion could be expanded more; better explain why she is being kept for so long and tested/monitored (connections to her father?). The realistic repercussions of Mr. Fleix's abuse to Nina (court, jail, etc.) as well as that of her parents could be fleshed out. Also, her parents' attitude reversal near the end and her spiral into drug use could be expanded.