Although I have a son and daughter at the tail-end of the much-maligned demographic group, Millennials (current age 18 to 33), they’re still a bit of a mystery to me.

The common perception of this “coddled” generation is that they’re obsessed with social media and technology, are in no hurry to grow up and move out of the house, have shelves groaning with trophies just for showing up, and want a life of meaning rather than work.

Whether or not there’s truth to this is beside the point.

What really concerns me is that this age group strongly prefers investing through exchange-traded funds (ETFs) rather than through good old fashioned stock-picking.

And now, adding insult to injury, Global X has filed with the SEC for a Millennial ETF that tracks a basket of stocks operating in sectors popular among Millennials. These include social media, digital media, ecommerce, mobile technology, travel and leisure, and the “sharing” economy.

Global X is a leader in developing theme-based ETFs such as the popular Global X Social Media ETF (SOCL), which has garnered over $100 million in assets. It also launched some duds such as the Global X Fishing Industry ETF (FISN) and the Global X Waste Management ETF (WSTE).

It’s still not known which companies will make it into the Millennial ETF basket, but we can guess at the usual suspects. Likely candidates are companies such as Apple Inc. (AAPL), Twitter Inc. (TWTR),Netflix Inc. (NFLX), Fitbit Inc. (FIT), Facebook Inc. (FB),Nike Inc. (NKE), and Costco Wholesale Corp. (COST).

Global X must be thinking that Millennials will invest in this ETF because they’re familiar with the companies in the basket. I think they’re smart enough to know that they can do much better with a more focused strategy.

Let me explain how I think ETFs should be used as part of an overall investment plan for younger investors…