One proposal under consideration came from a group of eight conservative and evangelical denominations.

Finally, conservative denominations have had a greater inflow of converts.

For almost 50 years women from conservative denominations had one more birth, on average, than other Protestant women did.

The remaining 30 percent of denominational change stems from the growing efficiency of conservative denominations in holding on to their own.

More than 95 percent were Christians identified with conservative Protestant denominations.

It is one of the oldest theologically and socially conservative denominations in the United States.

For example, many single people raised in conservative Christian denominations believe it is not necessary to actively pursue a partner.

"In some of the more conservative denominations it is silent, it's a secret, no one talks about it," he said.

By contrast, church membership at more conservative denominations like the Pentecostal churches rose by 127 percent during that period.