Humans and other mammals have an XY sex-determination system : the Y chromosome carries factors responsible for triggering male development. The "default sex," in the absence of a Y chromosome, is female-like. Thus, XX mammals are female and XY are male. In humans, biological sex is determined by five factors present at birth: the presence or absence of a Y chromosome (which alone determines the individual's genetic sex ), the type of gonads , the sex hormones , the internal reproductive anatomy (such as the uterus in females), and the external genitalia. 
Insulin is a hormone produced by the beta cells of the pancreatic islets of the pancreas. The pancreas produces insulin in response to the presence of high levels of glucose in the blood. Insulin stimulates cells, particularly in the liver and skeletal muscles , to absorb glucose from the blood and use it as an energy source or store it as glycogen. Insulin also stimulates adipocytes to absorb glucose to build triglycerides for energy storage. Our body produces higher levels of insulin following a meal in order to remove glucose molecules from the blood before they can reach high concentrations and become toxic to the body’s cells.
Leaving aside the fact that he had very little data to draw on, and that this could be a manifestation of arrogant masculinity telling women what their sexuality “should” look like, it might just be that there really was some truth in what he was saying…. to this extent: that generating a functional orgasm through G spot stimulation is entirely possible in women whose G spot has been sensitized (or has never shut down due to trauma). The vagina is innervated with a different set of nerves than the clitoris, and those nerves are linked to sexual responsivity.