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Families are conceived in a variety of ways, and that is especially true for people who face infertility in their quest to bring children into their lives. Some couples or single people choose adoption. Others favor fertility treatments and undergo up to years of testing, timing, and trying procedures to achieve the family they desire—often against mounting odds.

Of couples, approximately 10% will have trouble conceiving for a variety of reasons, from blocked fallopian tubes in women to low sperm counts in men. Sometimes a physical cause can be found and other times there is no explanation.

Women are more likely to have problems with fertility. The odds a woman 15-44 has ever had a problem becoming pregnant or carrying a pregnancy to term are 1 in 8.47. For men of the same age, the odds of ever having experienced a fertility problem are 1 in 83.33.

The frequency of fertility issues increases with age. A woman aged 40-44 is about twice as likely to experience fertility problems (1 in 5.59) as a woman age 15-29 (1 in 11.9). And men aren't immune from the effects of age. The odds that a man 15-29 has ever had an infertility problem are 1 in 250, but that becomes 1 in 50 for men 40-44.

For those who seek medical help for infertility, the effectiveness of treatment is also often tied to age. For women under age 35, the pregnancy rate after undergoing in vitro fertilization is 43%, but after age 42, the rate falls to 4%.

And in the United States, the cost of fertility services such as in vitro fertilization can be daunting, especially in states that don't require insurers to cover the treatments. A single IVF effort costs an average of $12,400, and repeated attempts multiply the cost. No statistics are kept on couples who seek cheaper alternatives abroad, but South Africa, Israel, Italy, Germany, and Canada crop up on lists for "fertility tourists."

Although conceiving and bringing just one child to term may be the fervent hope of many who are not childless by choice, sometimes there are additional embryos which have been fertilized but not implanted. Multiple embryos are often frozen to increase the odds a woman will have one or more successful pregnancies. But surplus embryos can pose ethical and moral dilemmas for women and couples who do not want more children, but may not feel comfortable donating or disposing of the extra embryos. Currently there are approximately 400,000 frozen embryos stored at US fertility clinics.