I see that some people in this thread need to learn how to science. Masculinity and testosterone are not the same things. If you're a "macho" man, that doesn't mean you have a higher level of testosterone than other men. There's a range of normal levels of androgens in males. I'm a transsexual man and have to get my levels checked periodically, so I know this. If you have a high level of testosterone (outside of the normal range), that's unhealthy and can cause a number of health issues. So I wouldn't be acting like it's a badge of honor.
Secondly, being "macho" is a socio-cultural thing. It's a behavior. Testosterone doesn't make you necessarily act one way or another. It can increase certain things, but we're not robots. Taking testosterone shots didn't make me a He-Man wannabe. It didn't turn me into a Tom of Finland drawing.
As for that study, I can't find many sources talking about it. CNN mentions it here, but they don't know what to make of it:
Modern life rough on men
Whatever it means, it doesn't mean that masculinity is dying or that "macho" men are on the decline.