The fertility of a couple is inversely proportional to their desire and/or perceived ability to have a child.
The Rule of Drama, as applied to parenthood. Couples who want to have children will have trouble not only conceiving, but adopting and using surrogates as well. People who don't want children, however, will be faced with unwanted pregnancies even if they used birth control, particularly if the conception was forced upon them. In fact, the page image leaves out rape, which is about 200% (that's right, you'll probably have twins). Teenagers, of course, will get pregnant their first time, double points if they thought they couldn't. The reason for this, of course, is obvious: "woman becomes pregnant with longed-for child immediately" and "woman doesn't want to get pregnant and doesn't" don't exactly make the most thrilling plotlines. At least the woman with a baby she doesn't want can give it up to the woman who is desperate to conceive—but, expect much angst along the way.
