#1 Myth #1: All hymens are made the same.
Just like people, not every hymen is exactly the same. The hymen is, generally speaking, a thin, pink membrane, but it can also be a thicker, white tissue. The edges can be smooth, or they can be fringed with many small tears or holes. And there are many factors that can affect it: genetics, hormones, physical activity, and development through puberty all play a role.
In rare cases, some women are even born without a hymen or have so little remnant of it after birth that it can't be detected..
#2 Myth #2: The hymen is a solid membrane.
The hymen doesn't actually form a strict barrier between the womb and the outside world; it's not a film that has to be punctured during intercourse. In fact, hymens that do stretch all the way across without an opening occur rarely - it's a condition called imperforate hymen, and it has to be corrected so that menstrual blood can flow through.
A more accurate name for the hymen is the "vaginal corona".