When we started homeschooling, both of my sons had life-threatening food allergies, and my younger son had just been diagnosed with neurofibromatosis 1, which made him more prone to learning disabilities. These weren't our first or only reasons to homeschool either, but I also felt it would me much less stressful to homeschool.
Six years later, ds11 has outgrown his food allergies, ds6 has no learning disabilities, but we still happily choose to homeschool for many reasons. :)