As opposed to coastal Alaska brown bear and interior grizzly bears, interpreting black bear gender from afar can be tricky for inexperienced. But, the basic principle applies to black bears as it does to the various brown bears.
A key thing to look for when deciding on the worthiness of a male bear - if you're strictly trophy hunting - is to pay close attention to the ratio between the head and neck when compared to overall body length. As with the brown bears, a really large male black bear will have a neck/head ratio that is at least 30% of his total body length.
A long, thick neck with very broad, flat shoulders and heavy forelegs and, a box-shape head with ears somewhat alongside [not directly on top] and with a well-developed muzzle are good indicators that the bear you're looking at is an older age-class male.
But, if it's your first go-round at black bear, any legal bear with a well-furred pelt is a worthy trophy. You shouldn't pass up an incidental bear on a DIY hunt if it's your first hunt for those animals. You can always go back on a bear-specific hunt at a later date and search for the big one.
Best of luck to you and have fun.
