What's in a word? The publishers of one of the world's best-selling Bibles are about to find out. They're releasing a "gender-neutral" version of the Good Book, replacing phrases like "son of God" with "children of God."

The International Bible Society said it would press ahead with the new version, to be called Today's New International Version, despite opposition from conservative groups.

Zondervan, of Grand Rapids, Mich., is the publisher that holds the rights to both versions.

The original New International Version has sold more than 150 million copies since being released in 1978. It will remain on the market.

The New Testament of the latest version is to go on sale in April, with the full text including the Old Testament expected by 2005.

Some conservative groups expressed concern that meanings would be altered with the changes.

"This is incredibly serious to evangelicals, how the Bible is translated,'' said Randy Stinson, executive director of the Council on Biblical Manhood and Womanhood. "We believe the Bible is the word of God, so changing these things deliberately is dangerous.''

Stinson's group, based in Louisville, Ky., works to preserve gender-specific language.

A Zondervan spokesman insisted the changes will reflect "the original meaning of the text."

"There's no social agenda,'' said Zondervan executive vice-president and publisher.

Some of the changes include: "sons of God'' to "children of God'' in Matthew 5:9, and "a man is justified by faith'' to "a person is justified by faith'' in Romans 3:28.

The new version is aimed at Protestants and will not appear in an edition recognized by Roman Catholic and Orthodox churches.

The King James version of the Bible has been the major U.S. sales competitor for the NIV edition.