Just to add that these are the Current Restrictions
A man may not marry his:
• Mother (also step-mother, former step-mother, mother-in-law, former mother-in-law, adoptive mother or former adoptive mother)
• Daughter (also step-daughter, former step-daughter, daughter-in-law, former daughter-in-law, adoptive daughter or former adoptive daughter)
• Sister (also half-sister)
• Father's mother (grandmother)
• Mother's mother (grandmother)
• Father's father's former wife (step-grandmother)
• Mother's father's former wife (step-grandmother)
• Son's daughter (granddaughter)
• Daughter's daughter (granddaughter)
• Wife's son's daughter (step-granddaughter)
• Wife's daughter's daughter (step-granddaughter)
• Son's son's wife (grandson's wife)
• Daughter's son's wife (grandson's wife)
• Father's sister (aunt)
• Mother's sister (aunt)
• Brother's daughter (niece)
• Sister's daughter (niece)
A woman may not marry her:
• Father (also step-father, former step-father, father-in-law, former father-in-law, adoptive father or former adoptive father)
• Son (also step-son, former step-son, son-in-law, former son-in-law, adoptive son or former adoptive son)
• Brother (also half-brother or step-brother)
• Father's father (grandfather)
• Mother's father (grandfather)
• Mother's mother's former husband (step-grandfather)
• Father's mother's former husband (step-grandfather)
• Son's son (grandson)
• Daughter's son (grandson)
• Husband's daughter's son (step grandson)
• Husband's son's son (step grandson)
• Son's daughter's husband (granddaughter's husband)
• Daughter's daughter's husband (granddaughter's husband)
• Father's brother (uncle)
• Mother's brother (uncle)
• Brother's son (nephew)
• Sister's son (nephew)
In Scotland, a man may not marry his great-grandmother or great-granddaughter and a woman may not marry her great-grandfather or great-grandson.
Stan