...an abbreviated version of Kinsey's argument looks like this:
1. In human beings, homosexuality has been demonstrated to be more common than previously assumed;
2. Therefore, there is a normal variation (or a normal “continuum”) of sexual attractions.
By replacing homosexuality with the examples of body integrity identity disorder and self-harm/self-mutilation in Alfred Kinsey's and the APA's argument (that is, if we follow the logic of Kinsey and the APA) the argument would be as follows:
1. In human beings, it has been observed that some people are attracted to and desire to cut themselves and remove their healthy body parts;
2. The attractions to cut oneself and remove one's healthy body parts have been demonstrated to be more common than previously assumed;
3. Therefore, there is a normal variation of attractions to self-harm; there is a continuum of normal variations of orientation to harm oneself.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4771012/