This different use of terminology can be maintained indefinitely if most Evangelicals avoid close contact with the groups with which they disagree - for example, contact with advocates of choice in abortion, gays, bisexuals, lesbians, and religious liberals. With their separate religious schools, magazines, bookstores, radio stations, TV channels, men's and women's organizations, local clergy associations, etc., it is not difficult for them to maintain this isolation. Some non-Evangelicals use the Evangelical definitions. Because of the limited space, definitions are necessarily very brief. This refers to the use of RU-486 to terminate a pregnancy.
Pregnancy starts at conception.
Pregnancy starts at implantation of the fertilized ovum in the womb. Human personhood starts at conception. Human personhood starts later in gestation. A therapeutic abortion is an intentional termination of a pregnancy, from implantation to viability. Homosexuality is a behavior.