As a mean average life span, yes, we do live longer today. We save many more babies these days than we did in the past, driving up the average. And we prolong the lives of people so sick they should have just died years ago, rather than drawing out the agony. However
the mean age of death is predicted to be lower for the current new generation than it is for their parents. This is because of two reasons. The health of the parents, and preceeding generations, in combination with the poor diet, lifestyle and environment of the children. If your a poor specimen of humanity, as is your spouse, your child won't be so top notch. This effect is compounded by the laziness and bad diet of the child. If this continues generation after generation, what the hell are we gonna be left with? For the last century, we in the West have been getting lazier, and our diet progressively poorer. Is it any wonder that while we have cured the diseases of poverty, we are spreading diseases of 'afluence' so fast?
This isn't total ramblings. In the '40s Dr Francis Pottenger carried out his
experiment with cats. He fed one group of cats raw milk, one pasteurised, one evaporated, and one sweetened condensed milk. They were all also fed supplements. The raw milk group was healthy, active, had good reflexes. Each other group was progressively worse than the last. Then he monitered each group as it produced litters, and the offspring was fed the same diet. The raw milk group produced strong, healthy kittens, that in time produced more strong healthy kittens. The pasteurised group had sickly kittens, who in time had kittens in worse condition. The other two groups were much worse, not being able to produced a third generation.
We will, in time, see similar results with our own children, unless we do something. Personally I see it as my responsibility to be as healthy as I can for the sake of my future offspring, and make sure they understand their responsibility.