Infertility is that the inability of an individual , animal or plant to breed by natural means. it's usually not the wild of a healthy adult, except notably among certain eusocial species (mostly haplodiploid insects). In humans, infertility is that the inability to become pregnant after one year of intercourse without contraception involving a male and feminine partner. There are many causes of infertility, including some that medical intervention can treat. Estimates from 1997 suggest that worldwide about five percent of all heterosexual couples have an unresolved problem with infertility. more couples, however, experience involuntary childlessness for a minimum of one year: estimates range from 12% to twenty-eight . Male infertility is liable for 20–30% of infertility cases, while 20–35% are thanks to female infertility, and 25–40% are thanks to combined problems in both parts. In 10–20% of cases, no cause is found. the foremost common explanation for female infertility is ovulatory problems, which generally manifest themselves by sparse or absent menstrual periods. Male infertility is most ordinarily thanks to deficiencies within the semen, and semen quality is employed as a surrogate measure of male fecundity. Women who are fertile experience a natural period of fertility before and through ovulation, and that they are naturally infertile for the remainder of the cycle . Fertility awareness methods are wont to discern when these changes occur by tracking changes in cervical mucus or basal blood heat.