Okay, here is the explanation directly from the company:
Gender Issues
"In the area of gender language, the goal of the ESV is to render literally what is in the original.
For example, “anyone” replaces “any man” where there is no word corresponding to “man” in the original languages, and “people” rather than “men” is regularly used where the original languages refer to both men and women. But the words “man” and “men” are retained where a male meaning component is part of the original Greek or Hebrew.
Similarly, the English word “brothers” (translating the Greek word adelphoi) is retained as an important familial form of address between fellow-Jews and fellow-Christians in the first century. A recurring note is included to indicate that the term “brothers” (adelphoi) was often used in Greek to refer to both men and women, and to indicate the specific instances in the text where this is the case.
In addition, the English word “sons” (translating the Greek word huioi) is retained in specific instances because of its meaning as a legal term in the adoption and inheritance laws of first-century Rome. As used by the apostle Paul, this term refers to the status of all Christians, both men and women, who, having been adopted into God’s family, now enjoy all the privileges, obligations, and inheritance rights of God’s children.
The inclusive use of the generic “he” has also regularly been retained, because this is consistent with similar usage in the original languages and because an essentially literal translation would be impossible without it.
Similarly, where God and man are compared or contrasted in the original, the ESV retains the generic use of “man” as the clearest way to express the contrast within the framework of essentially literal translation.
In each case the objective has been transparency to the original text, allowing the reader to understand the original on its own terms rather than on the terms of our present-day culture."
In addition, here is some more information about the ESV.
ESV Information
