A birth certificate is an official record of a birth. Parents are required to register a birth within six weeks. You may find someone born on 28th August 1859 was not registered until the following quarter which would be the December quarter rather than the September quarter. Up to 1875, registering a birth was not compulsory, so you could find some parents did not register a birth at all.
Obtaining a certificate is very important because it can help you to associate a child with their correct parent(s). If you have an ancestor who has a very common name such as Smith it can take on even more significance. There are numerous John Smith's in the GRO Index in any given year, and it is essential to make sure you have found the correct entry.
The short version of a certificate of birth only gives the name of the child, their sex, birthplace and date of birth. It is advisable to get a full birth certificate as it provides more information, such as the parents' name(s) and the mother’s maiden name so you can look for any possible marriage registration in the GRO Index.
If a time is listed this means the parents may have had more than one child born at the same time. The father's occupation is also entered, which can prove useful to the family historian as you may find your ancestor was mentioned in records of a company he may have worked for.
If the column for father's name is blank, this means the child could be illegitimate and it may prove more difficult to track down the possible father, although the father's name is sometimes mentioned in some way in the child's name.