Any ascendant or descendent of you and your spouse are considered disqualified. Children and their spouses, grandchildren and their spouses, parents and grandparents are prohibited. Family members such as siblings, nieces/nephews, aunts/uncles and cousins are allowed.
Partners, trustees and fiduciaries, as well as entities that any disqualified person or group of disqualified persons owns more than 50% of, are also prohibited. Please refer to IRS Code 4975 and Publication 590 for more details.