Even Screwtape suggests the fashion for shaving may be a way of removing or de-emphasizing basic gender differences.
If fashion dictates that a man of virtue is likely to be ignored by potential mates either because he chooses to grow a beard or because he can’t grow one that will bend to grooming, then the devil will have achieved his purpose.
Keep in mind that Screwtape was talking about encouraging a “fashionable” type for each sex: that is, in one age, teach men to value women who feign helplessness and foolishness, and in another age, teach them to pursue only women who look like boys. Likewise, teach women in general to dislike beards on all men, as a matter of fashion. In each case, a fashion was chosen so as to work against virtue and the willingness to fulfill the demands of married life, to bend people away from their innocent individuality in favor of social approval of inconsequential aspects of appearance, and in favor of falseness in general.
If a fashion teaches us to reject others for inconsequential reasons, to judge a man to be less of a man or a lesser choice as a husband because he is short or his beard is not full or because he has a five o’clock shadow by one o’clock, or to judge a woman as less feminine or a poor choice as a wife because she is too tall, too short, too thin, or too full or because her hair is curly when straight is the fashion or vice versa, then the Screwtapes will have achieved their purpose. This use of fashion by the evil one is to teach people to abandon choosing a mate based on considerations such as mutual spiritual help, fidelity, and the rearing of children, and to encourage impurity and infidelity in mind and, whenever possible, in body, too.
Any fashion that goes beyond grooming and being happily content with what you are and into forcing people into imitating some ideal that most will never be and few will be for long is something the devil will always encourage.