FORBIDDEN MARRIAGE LAWS OF THE UNITED KINGDOM

In England the list of forbidden marriages was drawn up by the Church of England in 1560 and remained unchanged until the 20^th century. I have reproduced the original list below. Because it is presented in a precise but rather complicated way I have transformed the list into a more easily understood form here .

Table 22 List of Forbidden Marriages

Table 23 Simplified List of Forbidden Marriages - A Table of Kindred and Affinity, (1560 list)

No cousins are mentioned, which is surprising since double first cousins (first degree and normal) are equivalent in their relationships to full and half sibs respectively. Also, half sibs are not mentioned, but I think the inclusion of half sibs is implicit in the general terms 'brother' or 'sister'.In the same vein half uncles, half aunts, half nephews and half nieces are implicitly included with their full counterparts.This is made clearer in later lists where half sibs are referred to specifically.

The full set of in-laws and step relatives are included to match the equivalent blood relatives of the same name except the following:

Stepsister	Stepbrother
Stepaunt	Stepuncle
Stepniece	Stepnephew

It seems strange excluding stepbrothers and stepsisters while including stepsons and stepdaughters. The first changes were made in 1907:

The 1907 Marriage Act removed no. 17 from the forbidden list (Wife's sister and Husband's brother), provided the first spouse in each case was deceased. Further changes followed in 1921, 1931 and 1949:

The 1921 Marriage Act removed no. 18 (Brother's wife and Sister's husband) provided brother or sister in each case was deceased.

The 1931 Marriage Act removed 6, 7, 8 and 9 (Aunt-in-law and Uncle-in-law) and 27, 28, 29 and 30 (Niece-in-law and Nephew-in-law), provided the relevant Uncle, Aunt, Niece, and Nephew were dead.

The 1949 Marriage Act confirmed the previous 3 acts and specifically included 'half blood' relatives.

Table 24 List of Forbidden Marriages (1949 version)

Table 25 Simplified List of Forbidden Marriages (1949 version)

To emphasise that the ten 'in-law' relatives, removed from the above list, could only marry the nominated person if all previous spouses were dead, a second list was included:

Table 26 In-laws Whom the Nominated Person Can Marry With the Above Restrictions (1949 Act)

Table 27 Simplified Version of Table 26

Current Regulations (1986)

Since 1949 there have been several further Marriage Acts culminating in the 1986 Act which brought the regulations up to date.

Blood Relatives

The following blood relatives are still forbidden to marry under all circumstances:

Table 28 Blood Relatives Forbidden to Marry

In 1960 the restrictions on the in-law relatives mentioned in tables 26 and 27 were removed. This means they are now free to marry irrespective of whether the former spouse is dead. i.e. It allows divorcees in this category to remarry.

The following in-laws can also marry without any restrictions, i.e. regardless of whether or not their first spouses are still alive:

Table 29 Further In-laws Who Can Marry Without Restrictions

The remaining step relatives can now marry provided they are over 21. Also, the younger person must not have been treated as a child of the older person's family and never, under the age of 18, lived under the same roof as the older person.

Table 30 Step relatives Who Can Marry With the Above Restrictions

The remaining in-laws can now also marry provided they are both over 21 and any former spouses must be deceased.

Table 31 In-laws Who Can Marry With the Above Restrictions

A new forbidden category has now been added covering adopted children:

Table 32 Relatives by Adoption Who Are Forbidden to Marry

Surprisingly marriage between unrelated adopted brothers and sisters (i.e. adopted by the same adoptive parents) is allowed.

The marriage laws for Scotland and Northern Ireland are similar to England and Wales except that Scotland also includes the following forbidden blood relationships:

Table 33 Further Forbidden Marriages (Scotland

Comments on the 1986 Regulations

My criticism is that there are still no sensible rules about marriage between 'blood' relatives. The only logical way would be to fix an obligate level of inbreeding beyond which it is not permissible to go. For example, if the maximum coefficient of relationship between partners is fixed at 1/8, this would limit the coefficient of inbreeding to 1/16 (6.25%). Marriages between single first cousins would then still be allowed but not between double first cousins. It would also allow unions between half uncle and half niece and between half aunt and half nephew. If this was introduced the list of forbidden marriages between'blood' relatives would then become:

Also any other unusual cousin or other relationships with an R value of 1/4 or above (see enhanced relationships.)

These figures could only be used as a guide since previous inbreeding (known or unknown), particularly in small closed populations could cause nominally low relationships such as first cousin (R = 1/8) to rise above 1/4. In these special situations it would be necessary to have a genetically qualified panel to assess the wisdom of certain marriages. The presence of any known inherited abnormalities in a family would also have to be taken into account.

Incest

Incest is defined by Martin (1990) as: ''Sexual intercourse between a man and his mother, daughter, sister, half sister or granddaughter, or between a woman over the age of 16 and her father, son, brother, half brother or grandfather. Even if both partners consent, incest is a criminal offence if the partners know of their relationship. It is punishable by up to 7 years imprisonment (or, with a girl under 13, by a maximum sentence of life imprisonment), but no prosecution can be brought without the consent of the Director of Public Prosecutions. The relationships listed above include illegitimate relationships. It is a statutory offence for a man to incite a girl to have incestuous intercourse with him, but being under 16, she would not be guilty of any crime if intercourse took place.''

Comments

Apart from religious constraints, the idea that incest laws should only encompass members of the close family stems from the desire to protect vulnerable children. From the biological point of view, however, all close inbreeding is harmful and undesirable, even when it involves relatives outside the nuclear family.

The above list excludes several relationships which are as close or even closer, in terms of the coefficient of relationship, than those within it. The following are some examples:

• Grandmother-grandson. This is a sexist exclusion, since although Grandfather-granddaughter incest is more likely to happen, when Grandmother-grandson incest does occur it is just as serious.
• Uncle-niece and Aunt-nephew sexual unions are excluded even though their coefficients of relationship are the same as between Half sibs and Grandfather-granddaughter (R = 1/4).
• Double first cousins of both types (first degree and normal), with R values equal to Full and Half sibs respectively, are also excluded. Likewise any of the other unusual cousin relationships described earlier, with coefficients of relationship of 1/4 or above. In view of the severity of the punishment for statutory incest I think these close cousin relationships should at least be included among the list of forbidden marriages.