Sandra leads worship in church. She teaches Sunday school, too. Her heart's cry is to make God happy. To the outside world, she seems purer than the average 20-year-old. Yet, inside she isn't. She can seem to do everything right, except this. It's her secret sin.

A man + a woman who aren't married to each other and are having sex = fornication. As God would have it, the mathematics begin and end here.

Fornication. It's a big word, isn't it? A big word for a simple meaning.

The F-word is found not only in the Christian Bible and the Jewish Torah but also in the Egyptian Maat. It carries a dual meaning: those who engage in sex and are not yet married and those who are married and cheat on their spouses. It is documented as a sin against one's body.

The sin of fornication plagues not just the Las Vegas pole dancer or Hollywood boulevard babe, it also plagues the "holy one" in the church. And Sandra isn't the only one who's falling prey to the big F.

There are others whose singing is so touching, who lead us in worship, who pray "earnestly," who give generously, who never miss church services, who are faithfully punctual, who pray in tongues and sincerely do all religious acts. They engage in all that is holy all while they are struggling with fornication.

In fact, the Church Girl Freaky Prank Call YouTube video with over 70,000 hits demonstrates the veracity of the "sexing Christian" epidemic.

To their credit, some are not necessarily the hypocrite type, but as Apostle Paul would put it, they are those who do what they do not want to do and vice versa. Their acts borderline on either a gnawing curiosity, addiction or idolatry.

Despite the struggle some go through to quit, they just can't kick the habit. Is it that it feels too good? She looks too good? Their body can't resist it?

One wonders whether there is a formula that results in fornication. Is there a common root for the fornication problem in the faithful Christian?

In his book, Religion Saves, Pastor Mark Driscoll, the founding pastor of Mars Hill Church in Seattle, Washington says sex outside marriage has become the world's norm.

According to Driscoll, over 5 million couples in the U.S. cohabitate. This is up from 1 million in 1978. This number doesn't take into account the number of couples who don't live together but who still regularly fornicate.

Cultural Timeline of the Evolution of Sex

In an article he wrote on October 26, 2011 called "Dating, Relating and Fornicating," Driscoll doles out a cultural timeline that demystifies the formula for sexual promiscuity in 2012.

1) Prior to the 1900s, "dating" was a slang term that referred to prostitution. A man who was going to pay a woman for sex told his buddies that he was "going on a date."

2) In the early 1900s, "calling" was the primary means of marrying. A young man would call on a young woman by going to the parlor in her parents' home. Her parents carefully oversaw these meetings, and expectations for everything from dress and food to length of time of the call was regulated and spelled out. This protected women from the kind of sexual assault that is common today by involving the parents on every level of the courtship process. It also limited the opportunity for a woman and a man to be alone and sin sexually.

3) By the 1930s, the rise of the automobile gave young people freedoms and mobility they never had previously, resulting in increased opportunities for men and women to go out alone and increased temptations for drunkenness and sexual sin.

4) By the 1940s, dating took on aspects of prostitution. Men treated women to nice dates, and in return they expected sexual favors. Naturally, those women who obliged were taken on more dates, and those women who didn't weren't asked out again.

5) The 1960s were the onset of the sexual revolution. This resulted in the greatest change in the social dynamics of singleness in the Western world, with orgies, casual sex, homosexuality, lesbianism, and bisexuality becoming increasingly socially acceptable. That decade saw the first widely available pornography magazine, Playboy, resulting in a shift in the way our society viewed the body and sex.

6) The 1970s cemented the concept of dating and casual sex as normative by removing any physical consequences through the legalization of abortion in 1973 and making no-fault divorce legal in 1974.

Fast-forward to 2012. Our decade is one characterized by music video vixens, reality show sex hook-ups and challenges, internet porn on demand and "sexting" serving as a pastime for junior high school boys and girls.

Gone are the days of Three's Company where you had to had to hide the fact that you're unmarried and living with a member of the opposite sex. There's no need.

Unfortunately, however, the annual rate of depression among those who live together are more than thrice higher than married couples. Yet, those who wait to have sex with their spouse are likely to remain faithful and report a notably higher happiness gauge. Even though the culture and times have changed, according to Driscoll, the underlying factor is - lies from Satan.

Leona Kim, 28, is a Christian single who thinks that most believers are controlled by their bodies and not their spirits, allowing the devil to capitalize on that weakness.

"You say, 'let me do it just today and I will repent...' kind of like misusing the grace," said Kim.

She further claims that more Christians are fornicating than abstaining.

"Just by the way they talk....being proud of sexually engaging with their boyfriends assures me that they don't just talk," she said.

Kim refused to comment when asked if she ever had pre-marital sex. Interestingly, during the reporting for this article, there were several "holy ones" who refused to comment on their sexual status, activities or indiscretions, citing that revealing those details would smear their reputation in their Christian circles.

Aneeta Adam, 29, believes that pent up sexual feelings are higher among Christian believers than non-believers.

"I was told that and I even experienced it," she said, who dated two pastors with similar sexual frustrations.

One relationship burgeoned from a friendship, the other from closeness that moved into intimacy. Both relationships resulted in regret.

In the end, Adam made a confession that it was all to fill the need of sexual pleasure. She claims that sometimes the guilt conscience is so intense that one can't even claim to truly enjoy the experience.

"One of my biggest fears is disappointing others. What if it [sex] does happen and the one time it happens, she gets pregnant," said Pastor Andre Harrison, 32, who is single and a radio personality on NEWDradio. "I would have really ruined my testimony and let down a whole lot of people who were looking up to me."

Pastor Yohane Tembo, Founder and Resident Pastor of Christ Alive Ministry Church in Malawi, shares a wider view. He said with certainty that three out of every five Christian singles he knows are committing fornication.

As to how he came up with the figures, he said, "This is not something that you can come up with by doing a statistical survey but through building a relationship with the Christian singles."

He said that most times after preaching on fornication, more than half of the participants meet him, confessing that they are doing it.

According to Pastor Tembo, the causes are quite clear.

Pastor Tembo's Formula for Fornication

1. Christian singles are lacking the purpose of life. They have nothing to drive them the right way.

2. There is a big gap between the mature Christians and the up and coming ones. As such, these newly born Christian singles are scared to share their real life issues or challenges so they can be helped.

3. The other cause is that immorality induces sexual feelings. For example, most young men are not aware that unholy dressing and impure stuff on the internet can influence them to fornicate.

4. Lastly, poverty. Tembo holds strong that there are Christian singles out there who are being forced to engage in sex acts NOT out of sexual pleasure. It is the case of the end justifying the means where one earns a living through the unintentional sale of one's body. This is very common for ladies. Unfortunately, even desperate children, including boys, are victims of the same. Tembo shared one true scenario where a young man was enticed into fornication by someone who knew he would agree because of his poverty-stricken state.

American author and philosopher based in Germany, Miriam Pia, argues that not all people who fornicate regret it, though. Many do it purely out of pleasure. Her formula is as follows:

1) She cites that some cultures and time periods crank out more promiscuous people than others.

2) Some people just want to have more than one lover. Some will fornicate and others will manage to have only one lover even though - in truth - they would like to have more.

She said fornicators are often people who are very passionate but are not married. They are frustrated from not having sex, so they have some. It's that simple.

Pia expressly stated that she would not describe the majority of her fornication as temptation, but rather a preferred choice.

"It was what I willed," she said. "I am a triple divorcee who wanted to have multiple lovers and have them. I only regret the negative impact with respect to staying married and people's hurt feelings," she said.

In her own right, she believes that both men and women should be free to have any number of lovers they choose, be it zero, one, 10, 100 or more. One person may want the celibate life while another may want just one lover and another may want just a few, she said.

Despite her controversial views, Pia said that she is aware of what others may profess, "I understand that not everyone agrees with this. I understand that Jesus and the Jews taught that people should have only one lover for life."

Chrisnatha Derosier, author of Through the Eyes of the King and President of Young Leaders of Today, LLC, believes that Christian singles are pressured by other believers to get married and then have sex. These singles may be made to feel like something is wrong with them if they don't marry by a certain age, especially if marriage is a pre-requisite for sex.

"This may breed loneliness which in turn may yield in actually giving in to the fornication temptation," said Derosier.

A sexual experience may make one feel like they're married, even it's just for a moment.

Some may even have sex for the hope of a long-lasting relationship - giving in just to please the partner at the expense of one's conscience, she said.

Furthermore, a common excuse that a single Christian may use is that it's okay to have sex because "they are engaged and will be married soon."

"God helps us to do what is right but we need to avoid certain situations, and knowing our weaknesses is imperative in overcoming the temptation of fornication," said Derosier.

Carlene Webb, 35, has been dating a guy for four months now and she now understands why it's so important to abstain from sex.

"We messed up twice in the beginning but for the last three months of the relationship, we decided not to do anything because it's important to get to know the person on a different level that has nothing to do with sex," she said.

Webb and her Christian boyfriend have Bible studies together and take walks on the beach to keep from fornicating.

"This is the first guy that I've been with that has been this strong in the Lord to where we can sit down and have this conversation and be open and up front about our commitment to God," said Webb. "Because he's so strong in this area, it helps me be stronger."

Their decision was deeply grounded in the belief that you can't adhere to just some of the things that God says in the Bible, and not all.

"It's not going to be easy because I'm attracted to him and he's very much attracted to me," said Webb. "But, if you have that commitment. You're going to say, "which one is more important?" If you eventually get married, the sex is going to be there, so what's the rush?"

Canadian online prayer coach Elisha Goodman cites sex outside marriage as one of the "9 Mistakes that Almost All Christians Singles Make."

"The Bible says clearly that our body is the temple of the Holy Ghost. We are warned against all form of sexual activity outside marriage, "said Goodman. "When you violate this crucial spiritual principle, you literally give the devil license to put you in a spiritual cage."

Goodman believes that if you are actively engaged in fornication, in the spiritual realm, the devil has posted a "Not Available" sign right across your forehead.

"Do you see beautiful singles wandering around in your church without even one marriage proposal? Or those who get proposed to just wake up to discover that it's been cancelled, delayed or rescheduled? For no plausible reason," he said.

It's a sign, he says. All things considered, their singleness may not at all be a coincidence.