Could just be the author's artstyle but good catch! daynight
I don't think it is the author's art style, it's definitely not his image, cause the shape of his hair/wig would definitely show a little, but it does looks like someone with no genders, someone that he knows more the shapeless interior than the external
I don't think anyone noticed, but in the reflection of ML's eye you can see the silhouette of a MAN