(a) He or she inserts a foreign object in the vagina, urethra, penis, rectum or anus of another person and the other person is incapable of consent by reason of some factor other than being less than seventeen years old; or
(b) He or she inserts a finger in the vagina, urethra, penis, rectum or anus of another person causing physical injury to such person and such person is incapable of consent by reason of some factor other than being less than seventeen years old. 2. Conduct performed for a valid medical purpose does not violate the provisions of this section. Aggravated sexual abuse in the fourth degree is a class E felony.