When couples trying to conceive must constantly get it on, the spontaneity and fun of sex can disappear faster than the time it takes to pop a fertility pill.

"At first you think, 'Hey, this is fun — we can do this whenever, and wherever, we want!'" says Carolyne, a Texas resident, in the alt.infertility newsgroup. "But then you get to the point where it becomes very humdrum and routine, almost robotic ... the romance isn't there." 

Although a third of couples become pregnant within a month after deciding to have a child, some 20 percent of healthy couples take more than a year to conceive. That makes for a lot of concerted babymaking, regardless of the mood or romance factor involved. 

All About Timing 

Because the female egg only has 12-24 hours following ovulation, couples are counseled to have sex every day or so in the time immediately before and after a woman ovulates, a period that usually lasts about two weeks. 

Sex on a timeclock isn't everyone's idea of romance — not that it has to be that way. For some couples, sex to conceive is a blast — at least at first, and especially if they're already making love every day. 

 
'It felt so great to know we were going to be creating a new life, part him and part me. It was a huge turn-on, actually' — Paula 
 

"We were already having sex like rabbits and didn't worry about any of this," wrote Shane and Ann Williams in an e-mail. "We just decided to have a baby and stopped using birth control." 

"It felt so great to know we were going to be creating a new life, part him and part me," agreed Paula, a woman who's trying to conceive and asked that her last name not be used. "It was a huge turn-on, actually." But when months went by without a positive pregnancy test, things got harder. 

Paula went on a fertility drug called Clomid, which can cause vaginal dryness and mood swings. "Combine these two side effects, and I think my husband would rather have slept in a different room, much less made love!" she says. 

Even without fertility drugs, the obsession with conception can overwhelm every other aspect of sex. 

"After more than a year of trying, we were right in the middle of relations and all I could think of was my right ovary," says Carolyne. "I started yelling at my husband, 'Aim right! Aim right!'" 

But the stress and depression of trying unsuccessfully to get pregnant can deal a hammer blow to libido and energy, making it progressively more difficult to conceive. As the months go by, couples can find themselves in a downward spiral. 

 
'You get to the point where it becomes very humdrum and routine, almost robotic ... the romance isn't there' — Carolyne 
 

"First I pump my body full of drugs in hopes of ovulation," wrote one woman on the alt.infertility message board. "Then the natural act of making love becomes this thing we 'have' to do. And, then there are all these rules: no oral sex, man-on-top, orgasm second. Ugh!" 

The woman was referring to some common beliefs: saliva is toxic to sperm, so no oral sex; the missionary position or rear entry are the best positions for conceptions; and that the female orgasm serves to suck sperm through the cervix and into the womb. The only problem: the scientific backing behind those theories is shaky. 

"The position does not matter, and the woman doesn't have to have an orgasm," says Dr. David Adamson, director of Fertility Physicians of Northern California. "If you had to have an orgasm to get pregnant, there'd be half as many babies in the world. Everybody has their own little secret [for conceiving], but if you look at the science it's just not there." 

Not that orgasms are a bad thing. Anything that makes sex fun should be encouraged, according to Dr. Linda Applegarth, director of psychological services at Cornell University' Center for Reproductive Medicine and Infertility. But it's also good to let your tired libidos rest a bit. 

"It's important to take a break," she says. "Couples look at me like I'm out of my mind — they think the month they take off is the one they would have conceived — but taking a vacation can be very helpful." 

Applegarth sometimes bans couples from having sex at all during their conception hiatus — knowing full well that they'll "cheat," and perhaps kick start their sex lives with some forbidden lovin'. She also recommends couples find new places to have sex, on the theory that shaking things up can bring back the spice. 

"And if can get up the courage," she says, "they'll have a funny story to tell their children when they're older."