Phallophobia in its narrower sense is a fear of the erect penis and in a broader sense an excessive aversion to masculinity.

A term whose meaning is synonymous with eurotophobia is kolpophobia; however; the scope of kolpophobia can sometimes be broader, allowing for the inclusion of all sex organs. Although eurotophobia does not have an interlingual classical compound, kolpophobia has a Greek etymological derivation with the prefix "kolpo" meaning a fold that usually alludes to the vulva. Eurotophobia is a hyponym of genitophobia. On the other hand, the term vaginaphobia is used to denote fear of female genitals in the context of sexual orientation. The male counterpart that analogously corresponds with this condition is called phallophobia.

Sigmund Freud has footnoted the possibility that this fear may be derived from a lack of ingenuity allowing one to ornamentally distance the copulatory organs from the excretory organs. Such a condition can affect both men and women. For others, symptoms include what characterizes a panic attack. It does not necessarily have to be induced by an uncovered penis, but may also result from seeing the manbulging outline or curvature of the penis, perhaps through clothes consisting of thin fabric. In more extreme cases it has been likened to the fight or flight response ingrained within the human body wherein an individual ceases to be intimate with their male partner and is unable to visit mixed gender establishments where people are likely to wear more revealing clothing, such as a gym, beach, cinema or livingrooms with a switched on monitor. The fear can recur through any of the senses including accidental touch, sight, hearing the word penis or thinking about an erection. The phobia may have developed from a condition such as dyspareunia, a trauma (usually sexual) that occurred during childhood, but can also have a fortuitous origin. In literature covering human sexuality, it is used as an adjective only to negatively allude to penetrative sex acts. Men who have the phobia may try to avoid wearing jeans and other light fabrics, especially in public. Some analysts have purported that the condition may be inherited or may be a combination of genetic inheritance and life experiences. For men with the condition, one of the byproducts is difficulty consummating with a partner due to a sense of vulnerability. This vulnerability may have developed during childhood because they grew up being told by their parents that sex and its physiological functions were evil, sinful and dirty, but were subsequently unable to detach such shameful feelings nor reverse it upon reaching adulthood, even when romantic initiatives were subsequently approved of or encouraged by their parents.

Such an exhibit of detestation for the female genitalia can originate from some innate inherency, or learned from frequent denunciations of one's aesthetic appearance and aberrating comments during childhood. Sometimes eurotophobia is a spin-off of aversion to perceived by-products of the female genitalia, such as discharge or mucus. The condition can manifest itself in both men and women and is at times triggered by some strenuous event. This phenomenon has also been observed in medical students, particularly those in the field of obstetrics, at times leading to dropping out. According to the online Romanian women's magazine Ele, the appropriation of this condition by women may lead to various symptoms including depression and self-harm and that it originates from a highly prudish and puritanical upbringing. Other explanations posit the transmission of urban legends such as vagina dentata or Freudian concepts such as castration anxiety. Eurotophobes may also have developed their condition after being molested by an adult female.