✔ 最佳答案
The answer is no.
It is a myth that it is illegal to enter a toilet of opposite sex.
In fact, in a lot of countries, including Hong Kong, it is not illegal to do so.
What makes it illegal is the person's behavior in the toilet. In Hong Kong, if you enter with illegal intend, then you can be charged for trespassing.
For example, it is not illegal if a female enter a male toilet with the intend to use the male toilet.