BusinessDictionary.com. Person or firm that endorses a three party agreement to guarantee that promises made by the first party (the principal) to the second party (client or lender) will be fulfilled, and assumes liability if the principal fails to fulfill them (defaults).
One in 2,000 babies are born with ambiguous genitalia and no one knows for sure if they are boys or girls.
Genetics 101 (very very basic and not complete in any way) 1 in 100 people are born with an intersex condition. Some go unnoticed all their life. A condition is discovered when a girl doesn't menstruate, a male's penis doesn't grow, infertility, or other issues arise. Many intersex people do not look at all unusual as babies. When babies are born - if they have what appears to be a penis they are a boy and if they don't a girl. They don't check to see what is inside. Some intersex conditions arise out of a missing sex chromosome or having an extra one (x, y, xxy, yyx).