Hell the yolk's the best part, the whites are where all the anutritive crap is (rendered safe by cooking though). I'm quite a bit past the pop-level nutrition ideas but I'm guessing you're asking about the yolks because of their cholesterol levels? Of these two a)high total cholesterol, b)low total cholesterol, low total cholesterol is more strongly linked to health issues than high total cholesterol.
One of the things you'll find when you go towards a healthy high fat diet is that your total cholesterol numbers will shoot up. This leads a lot of low-rate doctors to jump on the statins ship (which they get a cutback from your insurance company each year for prescribing btw). This a pretty juvenile reaction to a semi-meaningless figure such as total cholesterol. It doesn't take too much "advanced" comprehension to understand that there are different types of cholesterol and that they have differing effects on your overall health. On the surface there are the High Density Lipoproteins (technically not cholesterol but that's another subject), aka HDLs, aka "Good Cholesterol" and there are also Low Density Lipoproteins, aka LDLs, aka "Bad Cholesterol" as well as triglycerides. Technically there are a few others but they're rarely ever tested for.
If you got the "thorough" test which tells you your Total, HDL, LDL and Triglycerides levels then your doctor has still wasted your time. These tests don't actually measure the LDL, they just calculate it based off of the other numbers with a formula that is absolutely terrible for accurately gauging LDL levels if you're anywhere near close to healthy.
Of course in the end that doesn't really matter even if they did get close to guessing your real LDL levels. Reason being: just as there is "Good Cholesterol" (HDL) and "Bad Cholesterol" (LDL), there is also "Good HDL"/"Bad HDL" and "Good LDL"/"Bad LDL". (side note the beneficial effect of cardio raising women's HDL levels turns out to mainly be attributed to a rise in the bad subtype of HDL). Basically you can get good light fluffy versions of either which work wonders for keeping your system in tip top shape or you can get the small dense versions which have a bad habit of lodging themselves into arterial tears that occur from frequent carb consumption (of course without frequent carb consumption this risk lowers too).
Cholesterol is THE building block for most of your hormones. You can't be healthy without adequate levels of it. I think cholesterol and fats are the base of any healthy diet, no matter how many times the obese/diabetic/balding/frail Registered Dietitians I work with scoff at my heavy fat meals.
