Are members of the Mormon Church the only ones who will inherit the celestial kingdom?

Dear Gramps,
I am a little confused as I understand that only worthy members of the Mormon Church can inherit the Celestial Kingdom, yet I have heard that many people not of our faith will be able to inherit it also. Please can you enlighten me?
Margaret, from England

Dear Margaret,
There are only two groups of people who will inherit the celestial kingdom. One group comprises all those who have demonstrated faith in the Lord Jesus Christ, have repented from all their sins and who have been baptized by immersion by one having the requisite priesthood authority for the remission of those sins and who have remained true and faith to the covenants they make in the Lord’s Church throughout their mortal lives. This group includes those who lived on the earth without the opportunity to become acquainted with the gospel of Jesus Christ, but who would have believed and accepted the gospel if they had known it. These will be taught the gospel in the spirit world after their earthly probation, and the ordinance of baptism will be performed in their behalf by mortal proxies, either now or during the millennium.
The other group comprises all the children born on the earth who have died before the age of accountability. They are saved in the celestial kingdom through the merits of the great atoning sacrifice of the Savior.
Gramps