I believe it's closer to the natural order for men to be older than their female mate by 7 to 15 years. We don't see it often in this culture because maturing has become such a regimented process that people generally don't have life experience beyond the small, atomized age brackets to which they're constrained. That makes it difficult to find equal grounding and mutual philosophies with anyone who is more than a few years older than you. This becomes even more true when one considers the customary route of education. Until one graduates from college (around age 22 to 24), the overwhelming majority of social experiences have been with peers who are probably all within 18 months of each other and they've most likely not had to function as completely autonomous, independent humans in our society. Or, in layman's terms, it's harder for older people to date younger people cause younger people don't know shit and haven't actually lived yet.
Those are generalizations, of course, but I think they hold up to a cursory analysis of most people's social experiences in the western world.
Biologically, however, the raw chemistry undeniable. I am 32 years old now and have the advantage of being able to compare my current interactions with younger women (early to mid 20's) with the interactions I had with them when I was their same age. These days, those women are far more available to me than they ever were back then. Frankly, the sex is easy at this point. I attribute this primarily to the fact that in the past ten years, I have grown up a lot, established myself in an awesome profession, traveled, read, developed emotionally, physically, mentally and spiritually. I have a vision for my life in terms of where I am going and who I am / going to become. In short, I've become a man whereas before I was still a boy. Women find this really attractive by nature; they want someone who is strong and confident and stable. Men are usually just reaching this point in their 30's and women are looking to connect with it by the time they are in their 20's. Unfortunately, a lot of young women are still very immature to me despite being attractive and making themselves available. So while the chemistry exists, there is the social hindrance I mentioned in my first paragraph.
