Who’d have ever thought it? The youth of the ’60s and their younger siblings and friends who were teenagers and college students in the ’70s are graying, retiring and becoming grandparents.

This generation has become a viable market for a host of products, from hair dyes and skin lotions to arthritis medicine, cars and travel tours.

As one might expect, baby boomers are aging differently from their parents and grandparents.

“The baby-boomer generation continues to gray, but they are not accepting aging in the same way their parents’ generation did. Boomers are fit, have high incomes and want to stay fashionable and have fun. They are the targets of unprecedented marketing,” according to MarketResearch.com, one of many Web sites geared toward baby boomers and marketing.

Baby boomers are seen as the fastest-growing segment of the U.S. population. Statistics regarding boomers tells the story:

While the number of consumers in this 76 million-strong generation remains roughly stable over time, the boomer generation constitutes more than 26 percent of the U.S. population.

The current aggregate income of boomers is $4.1 trillion, and as boomers are in their prime earning years, this much-targeted demographic is more important to and poses a greater challenge for marketers than ever before.

The 50-plus age group numbers 74 million and growing. Every eight seconds, another person turns 50.

By 2010, the 50-plus segment in the United States will grow by 21 million, while the 18- to 34-age segment will grow by just 5 million.

Research findings show that 45- to 64-year-old Internet users are more likely than other age groups to own fax and copy machines, large-screen TVs and satellite dishes.

The boomer generation is diverse, and marketing reflects that, say experts.

PowerTrends Opportunity Profiles notes: “Low-income and ethnic boomer segments are growing in proportion and influence. Continued economic slowdown and current immigration policies are expected to further elevate the importance of these niche boomer segments.”

When boomers were growing up, they provided a viable market for children, adolescent, teen and college products. As aging consumers, they’re still a viable segment.

A 2002 report, “Lifestyles of U.S. Boomers,” says, “From its beginning, the baby boom generation has had a substantial impact on society, businesses and the economy. The generation’s large size ensured it would attract attention and many providers of goods and services have had to address the additional demands made simply as a result of the sheer numbers. This impact has been in all areas of consumer spending from the increased demand for baby products as this group produced the echo boom, the growth in sales of retirement accommodations in preparation for their aging.”

As the generation has matured, the nature of its demands has changed and this report discusses all the key areas of expenditure. Although members of the boomer generation share many characteristics, there is also considerable diversity within the generation. They are more racially and ethnically diverse than older generations, for instance.

Boomer households are almost evenly divided between those with children and those without, with people in lowermiddle- and upper-income brackets, the report adds.