What is marriage?

We've been discussing this issue in our Sunday School class for a couple of weeks now. Society has been redefining marriage for decades until it no longer resembles what God instituted for our benefit. We discussed how families need to have male leadership, and society doesn't like that because they are assuming that having a male leader of the household is implying that women are inferior. That is not what it is saying. It is saying that men and women are different and that they have different roles. This is what society wants to deny. When I was a college student majoring in English, we had this Bedford Glossary of Critical Literary Terms, which was helpful in writing papers, but also helped me to understand the world's thinking and reject it. It has this for the definitions of gender:

A term referring to the socially constructed identities man, woman, masculine, feminine. Some contemporary gender critics also use the term to refer to various sexualities (for example, heterosexuality, homosexuality, bisexuality, etc.) Gender is distinguished from sex, which is the biological designation of male or female. Unlike sex, which is anatomical, gender is widely held to be a product of the prevailing mores, expectations, and stereotypes of a particular culture. Thus, what it means to be "masculine" or "feminine" (rather than 'male' or 'female' )-what attributes and roles are assigned to each of these categorizations--is determined by culture (which is shaped primarily by the dominant group) and may vary from one culture to the next.

You can see why there is so much confusion these days when it comes to gender, what it means to be a man or a woman--because this culture wants to deny that men and women have differences beyond biological ones. They don't recognize that God created both of us, and He made two different genders for a reason. Genesis 5 says, "When God created people, He made them in the likeness of God. He created them male and female, and He blessed them and called them "human" (v.1-2).

So I don't think gender is a social construct, as my liberal English professors argued. Granted, society mores have changed---sayings such as a "women shouldn't work outside of the home" and "children should be seen and not heard" are not Biblical. I know that I have to work for a living--we need two incomes to pay all the bills and provide food etc. So I think the leadership they talk about, and the roles each gender plays is much deeper than who does what in the home, or who gets to make the decisions. (Frankly, I think a good leader would try to build a consensus anyway, and take everybody's needs and wants into consideration.) Any man who orders his wife about and forbids her from doing things, etc. doesn't love her.