In the authoritative biography of Rav Aharon Kotler, the two volume sefer "Aish HaTorah" (by the acclaimed biographer of many gedolim, Rav Aharon Sorosky shlita), it is related (in volume two on page 265):
A bochur in Lakewood allowed his beard to grow. One day, he shared his concern and anguish with Rav Aharon Kotler over the fact that his parents are vehemently opposed to his having a beard and are demanding that he shave the beard off. Rav Aharon Kotler responded that growing a beard is the "Malbush Yehudi," the traditional appearance of a Jew and the way our forefathers of all generations conducted themselves. Hence, the beard falls under the halachic mandate to uphold the traditional practices of our people (do not abandon the Torah of your mother' - see Pesachim 50b). 'Accordingly, you are not obligated to obey your parents' demand to remove your beard', Rav Aharon Kotler concluded.