“youth.” The Hebrew word translated “youth,” is naar (#05288 נַעַר), and it specifically refers to a boy or young male, and thus it can refer to a boy, youth, or young male servant, disciple, or slave. Due to the culture of the time, most of Proverbs was specifically addressed to males, with an underlying assumption that the knowledge would be important and applicable to women also. One thing that makes that clear is that the teaching of Lady Wisdom and the mothers in Proverbs is important (cp. Prov. 1:8 and 6:20), and those women had to be taught to become wise themselves, so it was not just males that were taught even if that was the primary emphasis in the culture of the time.
Another thing that justifies the use of more gender neutral terms rather than simply retaining words like “boy” with a specific male gender is how the New Testament writers cite passages out of Proverbs with a view to it being applicable to both male and females (e.g., Prov. 24:12 in Rom. 2:6; Prov. 1:16 in Rom. 3:15; Prov. 25:21-22 in Rom. 12:20; Prov. 3:11-12 in Heb. 12:5-6; Prov. 3:34 in both James 4:6 and 1 Pet. 5:5; Prov. 10:12 in 1 Pet. 4:18; Prov. 11:31 in 1 Pet. 4:18; and Prov. 26:11 in 2 Pet. 2:22). In other words, while the collection of Proverbs was primarily intended for a male audience (but see esp. Prov. 31:10-31), we have followed the example of the New Testament authors in widening the application of the verses to include both males and females by using gender neutral terms like “youth” rather than “boy” when it fits the greater context and scope of Scripture and does not unduly twist the meaning of the verse. The REV also often translates words that in Hebrew more specifically refer to males in a neutral fashion as “people,” “ones,” etc., see commentary on Prov. 2:12, “the one.”