In vitro fertilization, GIFT and related technologies--hope in a test tube.

In vitro fertilization (IVF) is demanding, expensive and inefficient. Nevertheless, tens of thousands of couples have undertaken the procedure because of their intense desire to have a biological child. Modifications of the current IVF process--simplification of ovulation induction and prediction of successful cycles; use of ultrasound instead of laparoscopy for egg retrieval; freezing of excess embryos for later replacement; and the substitution of GIFT (gamete intra-fallopian transfer) for IVF when it is indicated--may increase its acceptability to couples and improve success rates. Meanwhile, IVF has had tremendous impact on our understanding of fertility and should help physicians in their approach to infertility in the future. It has also ushered in a new era of genetic engineering whose potential we have not yet begun to realize.