The term אָדָם ('adam) has four different uses with reference to people in the OT:
1) a man as in a human person, whether male or female (e.g. Lev 13:2); 2) a man as opposed to woman (e.g. Eccl 7:28); 3) collectively mankind as a reference to all of humanity (e.g. Deut 8:3); and 4) Adam, the male individual who was the first human created and from which all mankind originates (e.g. 1 Chr 1:1).
So one must consider those possibilities when looking at the term in the early chapters of Genesis. A number of grammatical factors can come into play with respect to helping identify usage, and then context should be considered as well. To keep it simple here, there are two things to note about the use of the term 'adam prior to chapter 2. NOTE: All English quotations are from the NKJV.
- The first use of 'adam in Gen 1:26 is an anarthrous (lacks the "the" article) singular
2 that is immediately referred to by a 3rd masculine plural verb (יִרְדּוּ֩, "let them have dominion"), and so is clearly intended there as a collective term equal to mankind by use of the plural to refer to the singular term.
- The second use of 'adam in Gen 1:27 is articular (has the "the" article), so literally "the 'adam" or better, "the man." That reference is immediately referred to by a singular masculine pronoun ("in the image of God He created him"), and then a sexual distinction of "male and female He created them" (referring back to the prior reference to mankind). The lack of using the plural for the initial statement is significant in understanding the articular usage later.
So in the context of Genesis, the sexual distinction occurs earlier than chapter 2, since 1:27 refers to it as well, and that in the context of making an explicit singular statement to a masculine individual.
Moving to chapter 2, 'adam is found as follows:
- v.5 anarthrous, referring generally to "man" having yet been created (i.e. no individual human was yet created).
- v.7 articular, referring to the creation of "the man," with again a singular masculine pronoun reference following that "into his nostrils" God breathed life, and "the man" (a 2nd articular reference) "became a living being."
- v.8 articular, "the man" was put in the garden.
- v.15 articular, "the man" is declared to have been put in the garden for a purpose.
- v.16 articular, "the man" is commanded about what he can and cannot eat in the garden.
- v.18 articular, "the man" God determines was not good to be "alone," and it is "him" who the LORD plans to make a helper for.
- v.19 articular, "the man" (twice; the NKJV has Adam, the proper name, but see below) has animals brought to him to name.
- v.20 articular, "the man" has finished naming, but "for [the] man" (this second use in the verse is an anarthrous 'adam, but that is common when tied to a preposition, and thus becomes definite by context of referring back to the articular form before).
- v.21 articular, "the man" is put to sleep (again, "his rib" is a singular masculine reference back to "the man").
- v.22 articular, "the man" (twice), referring to the rib fashioned into the woman who is presented to him. NOTE: She is called the אִשָּׁה ('issah; woman) here still in contrast to the 'adam as an individual, male being (not as some "gender-neutral being" as the OP summarized Harper's position).
- v.23 articular, "the man" spoke about his helper.
- v.24 does not have 'adam, but an anarthrous אִ֔ישׁ ('ish) for "a man" in contrast to the 'issah as a general statement about how marriage will work once children are being born.
- v.25 articular, "the man" and "his" (again, masculine singular pronoun referent) woman ('issah, generally translated as "wife," so NKJV).
These contrasts to the articular "the man" ('adam) to "the woman" ('issah) continue in chapter 3, with two anarthrous exceptions, both occurring when used as objects of a preposition (3:17, 21); yet those in context undoubtedly refer to "the man" (or maybe his name, Adam). It is not until Genesis 4:25 that another, non-prepositioned anarthrous use of 'adam occurs, and that use is in reference to it being now considered his actual name, most likely for the first time in the text.
Why use 'adam as a name as late as 4:25 for the first time? The simple answer is that now there were many other "men" on the earth (at least Cain and Abel), where previously in chapters 1-3, there had only been "the [one and only] man" that needed to be referenced. That is, the articular use of 'adam stands in Genesis chapters 1-4, prior to 4:25, as a stand in phrase to refer to this one and only man, who does not need a name until more males are on the earth, at which time the designation for mankind (that he is the first of) also becomes his name.
So while lexical grounds allow for "humanity" as a meaning, there is essentially no contextual grounds to consider any of the articular references of 'adam to be anything other than the "male" prototype human that God initially created. All the pronouns reference the individual, the continued use as a comparison to the later created woman demonstrates the masculinity is inherent in the individual, and the conversion of the term to a proper name after other males come on the scene implies an original masculine reference all along.
1 Scott Smith, "Mankind: An Exploration of the Meaning of Image and Likeness," (Unpublished paper, Piedmont International University, Winston-Salem, NC, Sept 2011), 3. For lexical definitions verifying this, see HALOT's entries (I and III) or BDB's entry for אָדָם.
2 The term never occurs in a plural form; see Wilhelm Gesenius and Samuel Prideaux Tregelles, Gesenius’ Hebrew and Chaldee Lexicon to the Old Testament Scriptures (Bellingham, WA: Logos Bible Software, 2003), s.v. אָדָם.
3 The context clearly marks the term as referring to the individual, Adam, since he "knew his wife again" to bring forth their son Seth. The significance of the anarthrous is that as a rule, in Hebrew "the article cannot be prefixed to a proper name," (Friedrich Wilhelm Gesenius, Gesenius' Hebrew Grammar, E. Kautzsch and Sir Arthur Ernest Cowley, eds. 2nd English ed. [Electronic ed. Bellingham, WA: Logos Research Systems, Inc., 2003], §125.a, Logos Bible Software. This means that the prior articular uses were not, technically speaking, references to the proper name of Adam. Only the possible prepositionally prefixed uses in chapter 3:17, 21 may have been his name also, but see my commentary following this note above.
4 There most likely is a play on meaning between the masculine word 'adam (אָדָם) to the feminine word 'adamah (אֲדָמָה) that means earth, ground, or land (HALOT, BDB). The words are distinctly noted in Genesis 2:7 during the detailed description of mankind's creation. The union of the "dust of the ground" and the breath of God there indicates there is some truth to calling the planet "mother earth," and that from the 'adamah the 'adam is formed. So the term 'adam appears to symbolically remind of mankind's formation from the 'adamah, and in turn, that original man carries this "earthy" name as his own proper name, apparently being so named for the race of mankind ('adam) he began when he was first formed from the earth ('adamah).