Introduction

The substantial majority of young adults intend to become parents, but not all achieve a goal of conceiving easily when pregnancy is desired. The 1995 National Survey of Family Growth interviews conducted with 10 847 women suggested that 7.1% of married couples (2.1 million) in the United States met criteria for infertility (i.e. no contraceptive use and no pregnancy for 12 months or more; Abma et al., 1997), and 15% of women of reproductive age reported a past infertility-associated healthcare visit. In the United Kingdom, one in six couples has a fertility problem (Human Fertilisation and Embryology Authority, 2004). The American Society for Reproductive Medicine (ASRM, 1997) estimates that infertility affects females and males with almost equal frequency. Sources of female infertility commonly include ovulatory disorders and tubal or pelvic problems. Male infertility typically involves problems with sperm production (e.g. abnormal sperm density, motility or morphology) or impaired sperm delivery. Infertility remains unexplained following diagnostic work-up in approximately 20% of couples.

Approximately 44% of those with impaired fecundity (i.e. difficulty conceiving or carrying a pregnancy to term) seek medical services, with higher rates among those who are white, older, married, childless and more affluent (Chandra & Stephen, 1998). Over 50% of infertile couples who pursue treatment become pregnant (ASRM, 1997).