Well, just because it was unknown didn't mean it didn't happen. Just that progress before then was based on the idea that what came before was bad, and what we're trying to do now is good. Back then, there was progress -- there was just no ideology like "progressivism" which suggested that we might not have the best way now, but we'll keep learning until we get there.
And even with the whole ideology of progressivism, there is an opposite ideology which tells you that we have already found the 'natural law' or 'divinely ordained way of life'. And we must preserve this way of life, and fight those who suggest that the system is not yet perfect.
As a side note, I think a gender column is a neat idea. Wanted to offer a few insights into what I think is one of the best ideas I've seen for a new civics column.
http://forums.civfanatics.com/showthread.php?t=152909 <-- endorsement
I think you've made the right call in having two early game civics and two late game civics. Other columns, like religion, were set up to have a few early game choices with one big late game choice (which tends to be the favorite). Since it's hard to imagine three different civics before some kind of gender equality, it only makes sense that you have two and two.
I also think that the latter pair makes sense in the context of Civ. Both "Gender Equality" (e.g.: females as productive members of society, rather than baby machines) and "Sexual Freedom" (e.g.: full access to birth control and child care services) play off one another quite well. Implementing something like "Controlled Families" wouldn't make sense in a game where more population is generally a good thing (the same way that "Atheism" wouldn't make sense in a game where more religions are generally a good thing.)
The other choices -- "Polygyny" versus "Recognition" -- I think this is a fundamentally sound trade off... even if "Recognition" kind of sounds a bit tricky. I think Patriarchy might be a better fit, name wise, since it suggests that the state recognizes the 'nuclear' family as the main unit... the default might be better renamed to "Unplanned" or "Tribalistic".
The effects are trickier. Sexual freedom tends to lead to LESS population growth. hence the health benefit may seem logical but actually creates the wrong effect in Civilization 4. Also, in general, I think contrast is usually better for civics. (My personal preference, for game play.)
Unplanned: Default (There are some traditions that guide gender roles, but it largely depends on the individuals.)
Polygyny: +20% food. (Wealthier men take on multiple wives, resulting in large and prosperous families.)
Patriarchy: +3
, No Upkeep. (The state only recognizes a one-man-one-woman family, resulting in fewer poor single men.)
Suffrage: +25% production. (Women take on a significant role in the workforce.)
Sexual Freedom: +100% Great People. (With a liberal child care and contraceptive policy, women are no longer forced to choose between their career and their children.)
Just my two cents. Take them and run with them, or criticise them, or ignore them.