The sonnet 20 by William Shakespeare is one of the most famous early poems, addressed to a “Fair Youth”. Since it is a sonnet, it follows the Elizabethan structure that consists of 14 lines, organized into 3 quatrains and a rhyming couplet. The rhyme scheme is: ABAB CDCD EFEF GG. 

Its opening line, ‘A woman’s face, with Nature’s own hand painted’, immediately establishes the main theme: Shakespeare is discussing the effeminate beauty of the Fair Youth, the male addressee of the early sonnets. The poet says that the Fair Youth was created by Nature to be like a woman, with a woman’s face, a woman’s gentle heart, and beautiful eyes like a pretty woman’s. Therefore, in the first 6 lines, there is a description of the Young’s feminine beauty and in particular the speaking voice underlines the physical appearance of the Fair Youth, but yet he is still a man and, as you read in the second quatrain, his appearance attracts both men and women. Here, the verbs “steals” and “amazeth” are not casual, indeed while men are more attracted from the physical aspect of a person and their eyes are captured, women, instead, are captured by the feelings, emotions and words that characterize a man.

Considering the third quatrain, its topic is the gender of the Fair Youth, who seems to be closer to the female gender than the male one even because of the repetition of the word “woman” in the previous lines. Here, the speaking voice says that at the beginning the Fair Youth was thought by Nature to be a woman, but the Nature itself fall in love with him and give him male qualities with women’s ones too. 

Finally, in the rhyming couplet, there is not explained a solution for the trouble of the previous quatrains, because Nature cannot be changed by human beings and she chose the Fair Youth to be for women's pleasure, but the intelligent reader could find a possible and partial solution in the last line of the sonnet where the poet writes that he will have the Fair Youth’s love while women will use it only for benefit.

In my opinion, the message that Shakespeare wants to convey with this sonnet is that beauty has not got a specific genre because you can be attracted both by a man or a woman.