In point of fact, the English word "family" has changed substantially
in meaning during its history. It originally referred to the set of
servants or retainers attached to a household; only later did it
develop its meaning (now primary) of a group of people closely related
by blood or marriage.
>We are free to play
> around all we want with electrons or with the meaning of words like
> "gentleman" but when we attempt to alter God-ordained institutions we
> overstep our bounds. In short we sin. [There's another of those bothersome,
> God-defined words.]
I can see a plausible argument (given certain assumptions) from the Bible
that God ordained the institution of marriage. I can't think of any
argument that would show that God has ordained any particular grouping
as the only valid kind of family.