Here's a theoretical description of humanoid Cylon microbiology and genetics that you might wan to incorporate into a theory of your own:

Humanoid Cylons are biomechanical (rather than electromechanical) forms of artificial life. With artificial neural pathways constructed from "silica relay" microprocessors that imitate the complex neural networks of a complete human brain on the cellular level, they are the perfect fusion of the organic and mechanical. These Cylons are cybernetic organisms (cyborgs) and in the truest sense of the term; that is, they are cyborgs on a microscopic rather than macroscopic level. All of their artificial and biological components are integrated on a subcellular and even molecular level. They have mitochondria constructed from carbon protein-based nanomachines, cytoplasm composed of a synthetic chemical compound, and the molecular structure of their ribosomes are a hybridization of DNA molecules and synthetic DNA analogues programmed for the assembly of the artificial systems in replicated cells. All of the synthetics are indistinguishable from organics, even with medical analysis. The process in which all of the organic and inorganic systems are able to work and be grown together is far to complex for our 21st century technological comprehesion.

The only artificial components of the germ cells of humanoid Cylons are synthetic DNA analogues infused into the genetic makeup of the cells. These DNA analogues possess the "syntho-genetic" coding to use the bio-genetic coding of the appropriate adjoining germ cells (i.e. spermatozoa to ova) of humans to create fetuses that will naturally recreate the artificial cellular systems; although with only half the amount, making these hybrids more organic than mechanical. With one fully biological germ cell required for the development of the recreated artificial cellular systems, conception from two Cylon germ cells is impossible; therefore, humanoid Cylons can procreate with humans but not each other.