June is LGBT Pride Month. And the LGBT movement can take pride in many accomplishments. In the space of a few decades, gays have moved from being pariahs and criminals to being generally accepted in many parts of the U.S. The transformation in the political, legal and social landscape has been nothing short of astonishing.

Same-sex marriage is now legal in several states, and whatever the outcome of the litigation over DOMA or Proposition 8, polling data suggests an increasing number of people are willing to support marriage equality.

One major factor in the increasing acceptance of LGBT individuals has been the willingness of many of them to come "out," that is, to make their sexual orientation known to others. It is much more difficult to hate someone who you have known as a friend, colleague or relative. Negative stereotypes persist in part because many people don't have personal experiences that contradict the stereotypes.

For similar reasons, secular organizations such as the Center for Inquiry have urged atheists and other freethinkers to be open and candid about their beliefs. Many Americans remain bigoted toward atheists. One reason this prejudice remains is that many people don't have experiences that contradict all the negative information about the nonreligious that they have been fed for most of their lives, such as the claim that atheists are immoral or untrustworthy.

Or at least they think they have not had experiences that contradict these claims. The irony is that some of those who are prejudiced against atheists probably are acquainted with atheists -- they're just not aware of this. The reason they are not aware of this fact is that many atheists remain closeted. They have not revealed their skepticism to others because they are concerned about the reaction they will encounter -- and not without reason.

But, of course, they need to overcome this fear. Like the LGBT movement, the secular movement will not gain real traction unless and until the majority of atheists come out in the open.

So there's little question that encouraging fellow atheists to come out is a good thing; we will not make substantial progress unless people do come out, and coming out is a tactic that will have some success.

However, here I have to register a note of caution. I don't think coming out will have the same level of success for atheists as it's had for LGBT individuals. Why? Because even after we come out, some fear will persist. For some, the level of fear, the sense of being threatened, may actually increase.

There's a big difference between being gay and being an atheist. Someone can persuade you to be an atheist; no one is going to persuade you to be gay (no matter what the extremist anti-gay propaganda says).

I don't foresee a best-selling book entitled "The Straight Delusion" or "Heterosexuality Poisons Everything." The LGBT community wants acceptance; they don't want to persuade others to join their "team," and even if they had that objective, they would strive for it in vain.

By contrast, the amount of literature that has been produced in the last decade criticizing religious belief is extensive and continues to grow. Moreover, these critiques of religion seem to have had some effect.

Of course, many atheists have little or no interest in persuading the religious to abandon their beliefs. They merely want to be treated as equals and to end the influence that religion has on public policy. That doesn't matter. The realization that many atheists once were religious and then "lost" their faith has an unnerving effect on some of the religious. How far will atheism spread? Will I be next? Or my children?

Gays are different, but they don't send the message that heterosexuals are mistaken about their sexuality. On the other hand, not only are atheists different, but explicitly or implicitly, they are telling the faithful that they're mistaken about a core commitment (for some the core commitment) of their lives. As the number of open atheists increases -- and this seems likely -- we can expect some religious to become more defensive, more strident in promoting their beliefs. They will regard themselves as under attack.

No matter how accepting straight people are of gays, heterosexuals don't have to worry about becoming a small minority. When headlines proclaim that religion is becoming "extinct" in some countries, anxiety will be felt by some of the religious.

Nothing in the foregoing should be interpreted as suggesting we atheists should keep our beliefs under wraps to calm the fears of the religious. To the contrary, I firmly advocate the "coming out" of atheists and other freethinkers. Not only is it something we atheists should do to maintain our integrity, but, on the whole, it will be beneficial in reducing the level of prejudice against atheists. However, the path to acceptance may be a bit longer and rougher than it has been for our LGBT friends.