| A 2007 clip of “Chemistry”, by Swedish pop-singer Velvet, who sings about love and biogravity.|
The term seems to have been first used, albiet in a functional religious thermodynamics sense, in 1999 by author Holmes Rolston who stated that: “one can posit god as a countercurrent to entropy, a sort of biogravity that lures life upward.”  This latter theme, however, is an incorrect view. Correctly, it is the action of photons, the force carriers from the sun, which trigger earth-bound chemical mechanism (reaction), free energy, the main driving force, that lures life upward, and enthalpy that acts as the countercurrent to entropy. 
In popular writing, biogravity is seen as the force or mechanism that draws biological entities together, such as in two people falling in love. In music chemistry, for instance, the chorus to the popular 2007 song “Chemistry”, by Swedish pop-singer Velvet, is:
I feel the chemistry
Between you and me
when you're touching me
I feel the chemistry
feel the biogravity
I want you touching me
I feel you touching me
In a more technical sense, the description of what draws to human molecules (people) together is a thick subject full of details yet to be understood. When animate structures are categorized according to element-number, the trend emerges that the interactions of smaller entities, approximately 5-element or smaller molecules (see: molecular evolution table), are governed by the electromagnetic force, i.e. by the direct exchange of photons. As molecular entities become larger, up to the size of bacteria, a 15-element molecule, the gravitational force, specifically lunar influence, becomes a factor. In the human chemical reaction scenario, for instance, female sexual heat is cyclical, occurring every 27-days or one lunar period. Hence, the force that draws two people together in a state of love is a combination of the electromagnetic force and the gravitational force.  The gravitational force, however, may turn out to be an enhanced variation of chemical gravitation, resulting between large objects with mass.
1. Drees, Willem G. (2002). Is Nature Ever Evil?: Religion, Science, and Value, (section: “Order and Disorder”, pg. 69). Routledge.
2. Rolston, Holmes. (1999). Genes, Genesis, and God: Values and Their Origins in Natural and Human History, (pg. 364). Cambridge University Press.
3. (a) Schrodinger, Erwin. (1944). What is Life? Cambridge: Cambridge University Press.
(b) Thims, Libb. (2007). Human Chemistry (Volume One), (preview). Morrisville, NC: LuLu.
(c) Thims, Libb. (2007). Human Chemistry (Volume Two), (preview). Morrisville, NC: LuLu.