We all know its harder to trace female ancestral lines since the maiden name is often lost unless the marriage record is found...Lets have both males and females listed primarily by the name they were born with rather than later married names... Sources of information on the female's antecedents are often more easily shared by descendants of a second or third marriage with descendants of a first...if we can find each other!
I was surprised to find that an ancestor had been married more than once...and the stories shared were fascinating..
It is likewise harder to find female syblings of one's ancestors and see what their descendants have in family trees if they are not listed by the name common to all...that last name they were born with.
My tree contains all all female ancestors listed by their maiden name...except those who were arbitrarily changed to their married name when the Geni merger changed them to their married name. Those who have the same individuals in their tree but whose tree reflects a later marriage of some individuals will have those same individuals ...but named differently in their tree...Confusing eh?
I agree with Wendy that having the Birth Surname can be very helpful.
However, equally often it is the Married Name that helps me find records.
So for me, the setting I always want is the one which shows BOTH the Married Name and the Birth Surname.
[and I am one of those folks many of you probably hate - who often have a string of Last Names in the Last Name field when there have been multiple marriages]
I set it up that birth name is in brackets at the end. It is useful for both men and women, since it's not only women who change their name.
I have recently been working on Lev Nikolaevich Zinkovsky profile. It just so happens that he is very well known by his birth name, despite the fact that he changed it specifically because he didn't like it. So it is helpful.
Having said that, if the name has been changed, for whatever reason, it should be filled in. The arguments along the lines of "extra information makes it harder" are silly.
Plus it makes it actually more difficult when some people begin doing that. For example, in my family tree i have two people with the same surname marrying each other. So i have filled out both "birth surname" and "current surname" fields, so show that. If that would be on the border of your tree and somebody else's tree. It would simply appear as if we are talking about somebody not knowing the birth surname.
P.S. "Women and only women should change their last names during marriage" is a dumb rule, but we are here to do a global tree, and making it harder for each other isn't good.
Set name preferences for your preferred Geni views here
http://www.geni.com/account_settings/name_preferences
In a global shared tree it solves many problems to use facts.
For example, my Norwegian colleagues describe that prior to about 1900, married women in Norway were known by their patronymic lifelong.
Yet my Jewish colleagues describe that women married and took their husband's surname as far back as the introduction of surnames (which varied among different languages & cultures). Oh, and it was not at all unusual for a man to take on his wife's surname at marriage, either.
Luckily we have several surname fields.