Legal Definitions - in vivo fertilization

In vivo fertilization refers to the natural biological process where a sperm cell successfully fertilizes an egg cell within a woman's reproductive system, meaning the conception occurs inside her body.

Here are some examples illustrating in vivo fertilization:

• Example 1: Natural Conception
  After deciding to start a family, a couple, Mark and Lisa, engage in unprotected intercourse. Several weeks later, Lisa discovers she is pregnant. The sperm naturally traveled through Lisa's reproductive tract to meet and fertilize an egg within her fallopian tube.

  This illustrates in vivo fertilization because the entire process of the sperm uniting with the egg took place internally, within Lisa's body, without any external manipulation of the fertilization event itself.

• Example 2: Conception with Ovulation Tracking
  Sarah and Michael are trying to conceive and use ovulation predictor kits to identify Sarah's most fertile days. They time their intercourse to coincide with these days, hoping to increase their chances of pregnancy. Sarah later becomes pregnant.

  In this situation, despite the use of tools to predict fertility, the actual fusion of the sperm and egg still occurred inside Sarah's body, specifically within her fallopian tube, which is the definition of in vivo fertilization.

• Example 3: Intrauterine Insemination (IUI)
  A woman named Jessica undergoes an intrauterine insemination (IUI) procedure. Her partner's sperm is collected, washed, and then directly inserted into Jessica's uterus by a fertility specialist. A few weeks later, Jessica tests positive for pregnancy.

  Even though the sperm was medically placed into the uterus, the critical step of fertilization—the sperm penetrating and fusing with the egg—still happened inside Jessica's body (typically in the fallopian tube). This makes it an example of in vivo fertilization, as opposed to fertilization occurring in a lab dish.