Contrary to traditional "wisdom" men are not the sexual instigators in the human species.
And like Irving Berlin, most of us have noticed this at one time or other. But it is only recently that science is catching up.
Studies of other primate species besides ourselves such as Rhesus Monkeys and Bonobos (a species of chimpanzee) have surprised us by revealing that females are not only the sexual orchestrators, but that our social structures are built around that fact.
These discoveries seem to imply that among we humans, women are meant to be the sexual instigators, not men!
It's why girls mature faster than boys.
It's why women use their bodies to attract the "male gaze".
It means ads that feature sexy models are not examples of patriarchy objectifying women but of matriarchy objectifying men!
It's why men don't generally feel comfortable showing off their bodies but love showing off their athleticism or other abilities.
And it's why so many young men don't really seem to know naturally how to approach women without a course in pick-up artistry.
So where does this leave men?
Don't worry guys. Studies with apes reveal that society is a female invention. And for the most part, we males let them have it. But Society is not - by far! - all there is. We still have the rest of the entire universe to play in! Females are the sexual deciders, but that means males have more freedom to exist "outside society", to jump from society to society, to pick & choose what they take and what they leave. This is why men are more often the explorers, traders, builders, outlaws & dreamers.
So if you're a young man, don't worry about sex/reproduction. Let women worry about it. Concentrate on a career and having fun and they will come to you. By all means buy some weights and work on your body, but more importantly, develop a skill and show it off. Embrace your maleness and your freedom and enjoy all the lovely ladies putting themselves out there for their empowerment, your pleasure, and to keep society together.
Just keep one eye out for the cutie who is hanging around you hoping you'll "chase" her.