Re: why is ejaculation an involuntary response?

Hi Andrew!

All animals do not have the capacity to ejaculate and fertilize their female counterpart whenever they wish. Animals such as cow undergo estrous cycle (instead of menstrual cycle in human females). Therefore in animals such as cow, there is sexual stimulation only once every say 12 months! So, they can have sexual intercourse only once in 12 months, when there is a period of high sexual stimulation called "heat period". It lasts for about 18 hours. If the cow does not have sex during that time, it has to wait for another year to become pregnant.

Humans have muscles called "sphincter muscles" in their penis. It is due to the relaxation of this muscle that a person ejaculates. The reason as why a person can't stop ejaculation once it starts is because of the anatomy of the human body. Let me explain: You see, males have only one organ for excretion (i.e. urination) and ejaculation. (Females have different organ for excretion and copulation) So, once ejaculation starts, a person can't urinate because his urinary bladder has been blocked by another sphincter muscle called "urinary spincter muscle". As a result, until and unless the entire sperm is ejaculated, the ejaculation won't stop.

Every organism (knowingly or unknowingly) has the tendency to produce as many offsprings as he/she can. So, every ejaculation is meant to make the female pregnant and give birth to a child thus increasing the production of offsprings. It might be beneficial from the energy consumption point of view for ejaculation to be voluntary. But Nature hadn't thought about all these complexities when evolution of human species was taking place. We are evolving both morphologically and anatomically, and maybe in the future we would have ejaculation as a voluntary function. Who knows!