Everyone born in England and Wales on or since 1 July, 1837 should have had their birth registered by the state, which keeps a record of the event in the form of a registration entry. This shows information which an informant - normally the mother or her legal husband - provides to the registrar within six weeks of the birth.

There should be in existence two birth entries for each person back to 1 July, 1837 - the original with the Superintendent Registrar of the district where the birth took place and a copy at the General Register Office.

The birth certificate will tell you the:

• Forename and surname of the child.  The surname, which can be any name the parents choose, has been entered only since 1 April 1969. Before that date it has to be inferred from the father's surname.
• Sex of the child
• Date of birth
• Place of birth
• Father's name and occupation
• Mother's name and maiden name
• Informant's name and address

In the case of an illegitimate child, only the mother's name is normally given; before 1875, the mother was allowed to name any man as the father - he was not required to acknowledge paternity. An illegitimate child can now be issued with a birth certificate which gives him or her the surname of either the father or the mother. In order to reduce embarrassment for illegitimate children the so-called 'short' birth certificate was introduced in 1947. It is cheaper to buy than a 'full' certificate, but is of no genealogical value, and has restricted use these days.

This happens surprisingly often and there are several reasons why:

Registration in another district

Births are registered in the district in which they occur; this may not necessarily be the district in which the parents lived (the nearest hospital may be several miles from the family home, for example). Also, some early registrars were paid on commission, encouraging registration in the wrong district.

Birth not registered

In some parts of the country as many as 15 per cent of all births were not registered during the first decade after 1837. There was no penalty on parents' failing to register until 1875, many believing that registration was not necessary if the child was baptised. In 1844, the Registrar-General complained that thousands were escaping the net. 100% compliance was not achieved until about 1870.

Birth incorrectly indexed

Until modern times certificates were handwritten and subsequently indexed by a different registrar, so simple transcription errors were possible. Also, as illiteracy was widespread during the 19th century, registrars had no way of checking the correct spelling of surnames which were often written as they were pronounced: 'Hibbert', for example, might easily be indexed under 'Ibbert'.