The study did not find any differences in women taking estrogen and progestin compared to those taking only estrogen.

CNN: Health - Hormone replacement may influence mammography accuracy

For instance, Noven Pharmaceuticals (nasdaq: NOVN - news - people ) and Novartis (nyse: NVS - news - people ), which make a patch that delivers estrogen, emphasized that it was not clear that the results could be extended to their product.

FORBES: Wyeth Cautious On Long-Term Hormone Use

However, the side effects of excess estrogen produce more traditionally feminine traits in people, not masculine.

FORBES: Maine Women Sprout A #LittleBeard To Send BPA Message To Governor Paul LePage

Not only do our testosterone levels go down, but our estrogen levels go up and these female hormones coursing through our body can really wreak havoc on a man's functioning.

CNN: New dads can get postpartum depression, too

But that's not true for the most common kind of breast cancer, which is fueled by estrogen.

NPR: Study: Drug Can Curb Breast Cancer Recurrence

It isn't as if Daytona hasn't seen any estrogen along with all that testosterone. (No, these are not new products from Pennzoil.) As far back as 1977, a true trailblazer, Janet Guthrie, drove in the 500.

CNN: Danica Patrick races for history

Testosterone does not come straight out the adrenal glands, its made as DHEA and then is converted totestosterone or estrogen.

FORBES: Women Are Happier Than Men; Testosterone To Blame