Womb Tonic was first formulated by American chemist Harvey Wiley in 1898. The Klondike Gynite Rush had made gynite affordable to the middle classes for the first time in history. It was sold originally as a fertility aid to be taken by women struggling to conceive. It consisted then, as now, of a 0.5% infusion of gynite in a mixture of herbs and spices. Unfortunately it was found to have only limited success in treating fertility issues in already existing women. Perversely, it was found to be highly effective at creating fertile females from men.

If ingested in sufficiently high dosage, the man feminizes both in appearance and function, gaining a working uterus and ovaries, along with a compliment of fertile eggs even in men old enough to otherwise have passed menopause had they been born as a woman. Ovulation occurs immediately. Womb Tonic is formulated to revert after 12 hours except in the event of conception, which will lock the man's form until the culmination of the pregnancy.

'Willy's Womb Juice' proved highly popular. Until the development of IVF in the 1980s, it was often the only recourse for couples struggling to conceive. The husband agreed to carry the baby while the wife would call upon the services of her brother, father or other male family member to impregnate him, thereby ensuring she remained related to the child by blood.

The arrangement always took place behind closed doors to avoid drawing social disgrace on either the pregnant husband or his infertile wife. Nevertheless its use appears to have been an open secret and common enough for men to routinely take 9 month-long leaves of absence from work for 'sickness' without raising comment.

The product is much loved even today, still sold in its famous pink labeling, allowing men and women to divide the labour of labour so to speak, and used in cases where the woman is unable or unwilling to carry the fetus to term, as well being popular in gay relationships.

Hyperovulation becomes common at higher dosages. Side effects include triplets, quadruplets, and more.