Your genetic makeup may not be as fixed and unchanging as used to be believed. Researchers have discovered that there are inherited physical or mental traits that are not explained by sequences of DNA or by environmental factors.
There are mechanisms whereby genes can be turned on (expressed) or turned off (silenced). This is the relatively new field of biology called epigenetics.
It has become increasingly apparent to biologists that chemicals can turn genes on or off even long after exposure. And researchers now hypothesize that commonly-used, FDA-approved pharmaceutical drugs can cause persistent epigenetic changes. Epigenetic side-effects of pharmaceuticals may be involved in the etiology of heart disease, cancer, nerve and mental disorders, obesity, diabetes, leukemia, bipolar disorder, schizophrenia, infertility, and sexual dysfunction.