If you're in your 20s or 30s, one of the biggest decisions affecting your life likely will be made this fall.

It's not whether to get married. Or to buy a house. Or even to have and educate children. But it's a decision that could affect your ability to afford any or all of those things.

That decision, which will be made by Congress, is whether or not to give senior citizens, regardless of income or need, a prescription-drug entitlement in Medicare.

The House and Senate each have approved separate bills that would add a drug entitlement to the already cash-strapped Medicare program. Each bill was initially estimated to cost $400 billion over the next 10 years. New estimates peg them as being far more costly. Still, a Capitol Hill committee is hammering out the differences between the bills, and President Bush has indicated he'll sign whatever they put before him.

Our futures are being formed. But are we paying attention? Frankly, most lawmakers don't expect us to: We rarely make plans for the weekend until Friday rolls around, so it's a good bet we're not planning what will happen when we reach age 65 -- or how we'll obtain medical care when we get there.

But there's one very good reason we should pay attention as lawmakers tinker with Medicare. We (not they) will have to pay the bills.

Think about the extra $400 billion in taxes we'll have to pay over the next 10 years.

That's $400,000,000,000. How huge is that?

To give it some perspective, if you were paid $1 per second, every second of every day from the moment you were born, you'd be a millionaire in fewer than 12 days. But it would take you nearly 33 years to become a billionaire. That's right, 33 YEARS.

And still, to get the estimated cost of the proposed "reform," you must multiply that 33 years by 400. The resulting number should worry everyone -- especially young people.

Here's why: The 77 million baby boomers will begin retiring in 2011. Eventually, that'll nearly double the number of people on Medicare. By 2030, the typical household will pay $2,855 for Medicare, according to estimates from The Heritage Foundation. That's without a drug entitlement. Factor one in, and that number rises to $3,980 per household.

Heritage research also finds that between now and 2030, each household will pay an average $56,022 for Medicare, $16,127 of that for the drug entitlement alone.

Essentially, lawmakers are considering imposing a massive tax liability on young people. Keep in mind that while the cost of Medicare skyrockets, the cost of the rest of government (defense, Social Security, etc.) also will continue to rise, and we will have to pay for that, too.

There are poor seniors who genuinely need help and should get it. But three out of four seniors already have some form of drug coverage, many through former employers.

So why would Congress design a benefit for everyone when only a quarter of seniors need it, and make us pay for it? As we've seen, this bill covers everyone equally, rich or poor. Bill Gates, Ted Turner, Michael Jordan and all the other rich retirees won't go hungry if they pay out-of-pocket for prescription drugs.

What's worse, one-third of seniors with drug coverage through their former employers would lose it because of this bill, according to Congressional Budget Office estimates. Companies would save billions of dollars a year by dropping retirees because the taxpayer would automatically pick up the tab. So we get stuck with the check. Talk about corporate welfare.

But it doesn't have to be like this. We could make it better, for seniors and ourselves.

All we have to do is pay attention -- and now. Seniors vote in large numbers. They contact their members of Congress and stay involved. Unfortunately, too many of us in our 20s or 30s know who won on "Survivor" or "American Idol" but can't name our senator or congressional representative.

We have to change that. Members of Congress need to listen, and so do our parents and grandparents. Let's help those seniors who truly need help with their drug bills. But let Bill Gates and friends pay their own way.

No one is going to seek out our opinions. We have to speak up. We have to be engaged. We'd better start paying attention because, either way, we will pay.

Derek Hunter is a researcher at the Center for Health Policy Studies at The Heritage Foundation.