Can Government Change Physical Reality

The physical union of a man and a woman that can naturally results in the conception of children has existed for thousands of years. Over those same years those man, woman and children units that have hung together fared better in the evolutionary journey that has brought us to our own time. The reality of this unit is  described here in its biological and evolutionary dimensions. 

As languages developed and diversified, words were coined to represent real things of importance to human communication.  I would speculate that the most dramatic  events would give rise to the need for words that are descriptive of the components of the event. An example might be be the physical experience of childbirth giving rise to words like "mother" and "child" to describe the two persons involved in the physical reality of birth. As the child matures he wants to have a word for the other member of the unit and like "father" (or "ojciec" in polish), "brother" or "sister" to designate the elements of the reality. To refer to one such unit collectively words like "perhe" (in Finnish) or "Family' were coined. 

In most language groups there are also words designating the components of the biological reality we are considering,  thus the English words like "husband, "wife" and "marriage" to refer to the male, the female and the procreative activity involved.

Since I have based this analysis on physical or scientific reality I have not mentioned words of philosophical, existential, or religious origin/meaning like "friendship", "loyalty" or "love".

However, for words that designate objective physical (scientific) realities we need to ask, can a state change the meaning of a word by law or decree? Since it is currently politically correct to answer yes to this question it is appropriate to ask some follow up questions.

If a government changes the meaning of the word "marriage" (at least with in it's boundaries) does that action eliminate the physical reality that it formerly referred to? Most assuredly it won't.

 Since the definition of marriage currently being championed removes the procreative biology and the evolutionary strength  designated by the traditional definition of marriage it will have the effect of expanding the set of types of relationships that can be designated as "marriage". The very real thing previously designated by that word will continue to exist, perhaps as a subset of the new meaning, but will those that still value and want to talk about such procreative relationships be allowed to coin a new term to designate them?