Would the polyjuice potion be a workaround to the girls' dormitory stairway?

Question

The staircase to the girls' dormitory in Gryffindor is enchanted to become smooth when a boy is trying to climb it.

He was on the sixth stair when it happened. There was a loud, wailing, klaxonlike sound and the steps melted together to make a long, smooth stone slide. There was a brief moment when Ron tried to keep running, arms working madly like windmills, then he toppled over backward and shot down the newly created slide, coming to rest on his back at Harry’s feet. “Er — I don’t think we’re allowed in the girls’ dormitories,” said Harry

If a boy were to take a polyjuice potion of a girl, would they be able to pass the staircase? If there is no concrete evidence pointing to one way or the other, is there at least any references as to whether the polyjuice potion can fool enchantments or spells similar to this?

Answer 1

We don't know for sure, but it would probably work

We never see it tested, and we don't know what enchantments the stairs use for detection (although whatever it is, we can reasonably assume it triggers the Glisseo charm). But there are a few observations we can make.

The stairs seem more interested in what you are than who you are. While the magical capability to determine one's "true self" certainly exists (such as those employed by the Marauder's Map), it seems like it would be overkill for the stairs to have an enchantment that thorough and specific, especially when you consider that there are other ways around such a simple deterrent for the truly determined (brooms, levitation, etc).

This can be corroborated by the fact that the majority of Hogwarts' protective enchantments are equally naive. Why would the common rooms or headmaster's office use simplistic passwords when they could use more reliable/secure identity enchantments? A basic enchantment to check for male/female seems to be the most likely implementation, for which polyjuice is sufficient enough to fool.

Answer 2

Probably not, but it may work, I think it would depend on the date of invention of Polyjuice. A good number of magical relics like the Marauders' Map are not fooled by the Polyjuice transformation but those are all items that post-date the invention of Polyjuice Potion; the castle, and thus its defenses and enchantments, is old so if the creators didn't take such a possibility into account, because "of course you can't do that with magic, we would know", then you might get away with it.