Why do people have fetishes, such as foot fetishes?
How do such fetishes form? Are childhood incidents the main cause of fetishes? Are fetishes a sexual disorder?
Having one or more fetishes is very widespread, and thus rather normal.
The prevalence of fetishism is not known with certainty. The majority of fetishists are male. In a 2011 study, 30% of men reported fetishistic fantasies, and 24.5% had engaged in fetishistic acts. Of those reporting fantasies, 45% said the fetish was intensely sexually arousing. In a 2014 study, 26.3% of women and 27.8% of men acknowledged any fantasies about "having sex with a fetish or non-sexual object". https://en.wikipedia.org/wiki/Sexual_fetishism
A disorder is per definiton something abnormal
disorder [dis-or´der] a derangement or abnormality of function; http://medical-dictionary.thefreedictionary.com/disorder
So the answer to your question would per definition be: No. Having fetishes is normal and not a disorder.