The Body Type program asserts that there are four major glands in the human body (pituitary, thyroid, adrenal, and gonadal) and that each individual has one "dominant gland". Ann Louise Gittleman stated that Abravanel developed these ideas as an expansion of speculations by Henry G. Bieler and noted that this was done, "Without directly monitoring the behavior of any gland..." According to Abravanel, men can be P-types, T-types, or A-types, based on the dominant gland, and women can be P-types, T-types, A-types or G-types (only women can be G-types due to the purported overall influence that a woman's sexual glands can have on her body).
The Body Type program suggests that an individual's dominant gland determines their personality type, with men categorized as P-types, T-types, or A-types and women as P-types, T-types, A-types, or G-types. This system is based on the idea that each person has one "dominant gland" which influences their behavior.