There are also many synthetic sex steroids. Synthetic androgens are often referred to as anabolic steroids . Synthetic estrogens and progestins are used in methods of hormonal contraception . Ethinylestradiol is a semi-synthetic estrogen. Specific compounds that have partial agonist activity for steroid receptors , and therefore act in part like natural steroid hormones, are in use in medical conditions that require treatment with steroid in one cell type, but where systemic effects of the particular steroid in the entire organism are only desirable within certain limits. 
But the findings provide the first hint that gender may have specific scents, and that the human nose and pick up on them. The study also suggests that the human nose may be relaying information about much more than smells that the brain processes on a conscious level. Recent studies, in fact, have confirmed that our olfactory sense is capable of picking up one trillion smells , and that we can pick up whiffs of illness when somebody’s immune system is activated. There’s even evidence that the human nose can smell age – an evolutionarily helpful skill that distinguished younger, more fertile mates from older ones. We are only beginning to understand what the nose knows, and we imagine ensuing research will continue to surprise and baffle us all.
Steroid isolation , depending on context, is the isolation of chemical matter required for chemical structure elucidation, derivitzation or degradation chemistry, biological testing, and other research needs (generally milligrams to grams, but often more  or the isolation of "analytical quantities" of the substance of interest (where the focus is on identifying and quantifying the substance (for example, in biological tissue or fluid). The amount isolated depends on the analytical method, but is generally less than one microgram.  [ page needed ] The methods of isolation to achieve the two scales of product are distinct, but include extraction , precipitation, adsorption , chromatography , and crystallization . In both cases, the isolated substance is purified to chemical homogeneity; combined separation and analytical methods, such as LC-MS , are chosen to be "orthogonal"—achieving their separations based on distinct modes of interaction between substance and isolating matrix—to detect a single species in the pure sample. Structure determination refers to the methods to determine the chemical structure of an isolated pure steroid, using an evolving array of chemical and physical methods which have included NMR and small-molecule crystallography .  : 10–19 Methods of analysis overlap both of the above areas, emphasizing analytical methods to determining if a steroid is present in a mixture and determining its quantity.