You can donate cord blood for free to a public bank. Obviously you're not guaranteed that it won't be used by someone else before a sibling potentially needs it, but the chances of it being useful to your own family are almost zero anyway -- not exactly zero, but if you were making a list of the ways to best increase your life expectancy given $5k to spend, I doubt it would even make the top 1,000 options in terms of expected ROI.