Constitutions are floors, not ceilings.
Rights granted by the U.S. or individual state constitutions are meant to define a standard below which laws and law enforcement should not fall. This is important to the cause of gender equality because most state constitutions have very clear language expressing some iteration of the idea that laws must apply to both genders equally.
Generally people think that the First and 14th Amendments to the U.S. Constitution are our biggest allies. They certainly help but they are pretty far removed from the conversation between a bare-chested woman and the confused police officer standing before her in the street. Constitutional arguments matter in appellate courts, months or years after an arrest. U.S. Constitutional arguments are also murky, convoluted and often downright anti-intuitive.
For example, the 14th Amendment basically says that we all have the right to “equal protection” under the law. However the Supreme Court has repeatedly found ways to limit those protections by finding “compelling” reasons for inequalities to exist (think women in combat roles for example.)
With that said, the 14th Amendment was influential in the famous 1992 New York case in which the “Rochester 7” established a woman’s right to appear bare-chested in public anywhere in New York State.
However in years past (long past sometimes) the 14th Amendment has not always protected women from prosecution for appearing bare-chested. It depends on which court is hearing the case. Many efforts to legalize female bare-chestedness through trials and appeals have been successful (Ohio, Vermont, New Hampshire, Maine, New York, Texas, Washington D.C. etc.) but a few have fallen short, though most of those were more than a decade ago.
State constitutions are much more powerful allies in our efforts to assert equality. State supreme courts hear far more cases than the U.S. Supreme Court and many state supreme courts interpret their constitutions very literally. Maryland, for example, my home state, has very clear constitutional equality language and the Maryland Supreme Court has repeatedly held there to be no compelling reason to treat the genders differently under the law.
Here’s where this gets juicy and important and exciting for bare-chested women… if your state’s constitution has an equal rights clause somewhere in it, and they almost all do, file that away in the back of your mind. Somewhere in a conversation this will neutralize a detractor’s main argument, which will almost always be to assert that men and women are different. No matter if we are different, I answer, because our constitution guarantees us equal treatment anyway. It’s basically a way of saying you can disagree with what I’m doing, but you can’t do anything about it. (Important Note: this may not fly in court, but it has been very successful in deescalating people objecting to my bared breasts and has kept them from calling the police.)