Open a form to report problems or contribute information

1 Introduction 2 Message details 3 Upload file 4 Submitted
Page 1 of 4

Help and advice for Consanguinity

If you have found a problem on this page then please report it on the following form. We will then do our best to fix it. If you are wanting advice then the best place to ask is on the area's specific email lists. All the information that we have is in the web pages, so please do not ask us to supply something that is not there. We are not able to offer a research service.

If you wish to report a problem, or contribute information, then do use the following form to tell us about it. We have a number of people each maintaining different sections of the web site, so it is important to submit information via a link on the relevant page otherwise it is likely to go to the wrong person and may not be acted upon.


Consanguinity is basically "how close are you related?". Laws to prevent consanguinity (in other words, "don't marry your sister"), have been passed down from ancient times. The Marriage Act 1949 as amended by the Marriage (Enabling) Act 1960 establishes this list:

  • generally, uncles may not marry nieces, nor aunts their nephews
  • first cousins may wed
  • and a woman may marry her husband's brother, uncle or nephew if her marrige has ended by death or divorce.

Many Americans may be surprised to hear that first cousins may marry, because it is forbidden in many American states, as well as other parts of the world. The Marriage Act of 1986 (Prohibited Degrees of Relationship) makes further provision for the marriage of persons related by infinity (or marriage). The reason for these prohibitions is, firstly, public policy, and secondly, the genetic risk.

Here is the list as it appeared in a Church of England Book of Common Prayer:

A Man may not marry his: A Woman may not marry her:
  • Mother
  • Daughter
  • Father's mother
  • Mother's mother
  • Son's daughter
  • Daughter's daughter
  • Sister
  • Father's daughter
  • Mother's daughter
  • Wife's mother
  • Wife's daughter
  • Father's wife
  • Son's wife
  • Father's father's wife
  • Mother's father's wife
  • Wife's father's mother
  • Wife's mother's mother
  • Wife's son's daughter
  • Wife's daughter's daughter
  • Son's son's wife
  • Daughter's son's wife
  • Father's sister
  • Mother's sister
  • Brother's daughter
  • Sister's daughter
  • Father
  • Son
  • Father's father
  • Mother's father
  • Son's son
  • Daughter's son
  • Brother
  • Father's son
  • Mother's son
  • Husband's father
  • Husband's son
  • Mother's husband
  • Daughter's husband
  • Father's mother's husband
  • Mother's mother's husband
  • Husband's father's father
  • Husband's mother's father
  • Husband's son's son
  • Husband's daughter's son
  • Son's daughter's husband
  • Daughter's daughter's husband
  • Father's brother
  • Mother's brother
  • Brother's son
  • Sister's son

What was it like in Medieval times?

According to Ancestral Trails, by Mark D Herber, these were the "prohibited degrees" of marriage, according to the Book of Common Prayer, 1662:

  1. brother or sister (or their spouse)
  2. parent, grandparent, aunt, uncle, child, or grandchild (or their spouse)
  3. niece or nephew (or their spouse)
  4. spouse's child, grandchild, parent, aunt, uncle or grandparent.

Statutes of 1907 and 1921 made an exception at a. above, allowing people to marry the spouse of the brother or sister, if that brother or sister had died. Some further exceptions were made in 1931, 1949 and 1986 so that, for example, a man was allowed to marry his deceased wife's niece, aunt or widowed mother.

For more information, go to Guy Etchells website.