I don't believe in blindly adhering to tradition, but I also don't believe in disregarding it. There is a solid middle ground to be found in modernizing tradition. >gender roles
Well, yeah, there's a reason for these. It's somehow controversial to say so, but the minds of men and women are optimized for different tasks. This was necessary throughout time in order to ensure that a) there was always someone providing, and b) there was always someone nurturing. In modern times this is no longer strictly necessary, but there are still consequences for disregarding it. Masculinity and femininity are polar opposites. They compliment each other and provide structure within relationships and families. When you have spouses butting heads (trying to share the masculine role), you end up splitting off into two directions, which does not make for a cohesive family. When you have spouses waiting for the other to lead (trying to share the feminine role), you end up going absolutely nowhere. Women like leaders, and men like to be supported in their leading. Many people will deny this, but it's hard to deny the evolutionary cause.>sex/promiscuity
This also has its basis in fact. Studies have demonstrated that a greater number of sexual partners is associated with lower marital satisfaction. Sex establishes a bond, and there's no way to continually form and break bonds without losing a bit of the magic along the way. There's also the obvious: someone who enjoys having many sexual partners will be "giving something up" upon marrying, leading to worries of infidelity and dissatisfaction. And, of course, when a man knows his partner has had others before him, he may worry about performance, size, etc. >lineage
It's not so easy to back this one up with anything concrete. I guess this is more of an aesthetic thing than a rational one: it feels good to be proud of one's family, or to be proud of one's country/heritage. There's a sense of pride involved, and a person who is receptive to this feeling will likely feel some pressure to contribute to this "legacy." This is a very good thing, when you consider the number of people who are content to drift along, as >>927
This is a trickier one. Abrahamic religions come with a host of difficulties (although I do feel very positively about the effect of Christianity on the west, especially protestant belief). These scriptures are in many ways outdated, and it can be difficult to apply their rulings to modern life, especially when interpretation is so divided (particularly among protestant/liberal sects of Christianity--and liberal Judaism is probably worse). This is where modernization comes into play. For me, the answer has been Christian Deism. Many others have found comfort in "modern spirituality," which is not my cup of tea, but involvement in spirituality is really all that matters; the particulars are not so important.
Tradition on its own carries a great deal of value. Gender roles, patriarchy, religion, marriage etc. are all just expressions of how humans have been able to operate best over the years. And yes, "this is how it's always been done" does not make for a very compelling argument by itself. But take some time to think about why these things have been done this way for so long and you may just find yourself falling into agreement.
 It seems the source for this is down. There are lots of secondary sources around, though.