Intending to father a child in the 3 months following the study or are unwilling to abstain from sexual intercourse with pregnant or lactating women Unwilling to use a condom/spermicide in addition to having their female partner use another form of contraception such as an IUD, diaphragm with spermicide, oral contraceptives, injectable progesterone, subdermal implants or a tubal ligation if the woman could become pregnant from the time of the first Assessment Visit until 3 months following the study.