I was looking at the Hebrew of Genesis 1:27 again tonight and noticed it's not quite as obvious as I thought. I still think the normal interpretation is correct (i.e., that of the NRSV, NIV2011, NLT, Message), over against the ESV and HCSB. It just isn't as obvious as I was saying.
Here's the Hebrew (it goes from right to left):
וַיִּבְרָא אֱלֹהִים אֶת־הָֽאָדָם בְּצַלְמֹו
in his image the 'adam God and he created = "And God created the 'adam in his image"
בְּצֶלֶם אֱלֹהִים בָּרָא אֹתֹו
him he created God in the image of = "In the image of God he created him"
זָכָר וּנְקֵבָה בָּרָא אֹתָֽם
them he created and female male = "male and female he created them"
Where I was wrong is that I thought the "him" of the second line was a "them," but the exegesis is still the same:
1. The "him" of the second line must include both male and female because the third line unpacks the second.
2. Therefore, the 'adam is not a reference to the person Adam or to "man" as a reference to males. It is a reference to humankind in general.
It is difficult to bring this into English. I still maintain the NRSV is the best rendition. Languages like Hebrew have to pick a gender for the object of the second line, and since 'adam is grammatically masculine, "him" was the appropriate grammatical choice. But in English, him means a male, even though in Hebrew it is not sexual here.
So I stand by my claim that by choosing to go with "him," the ESV and HCSB actually change the meaning into a masculine bias it did not have in Hebrew.