The roles of gender have been mostly considered as cultural.
There is no doubt that biology affects the both gender at some
extent, but it has been found that culture plays big role in gender
roles.
Biology affect the physical abilities, appearance, size and
strength of a person, but culture affects the behavior of person
and plays major role in interest, attitude and skills.
Culture shapes the children and grown up with certain values
and beliefs, which they follow through their life. There are some
cultures which are more patriarchal and some are more matriarchal.
Some behaviors are acceptable in some cultures while some are
not.
Everyone is shaped by their childhood to behave like what is
acceptable, such as "behave like a lady", "boys don't cry", and
they follow those rules, therefore we can see that cultures plays
bigger role in gender roles.