Under UK law, an embryo has no rights until it is 14 days old. After this it has limited rights. With the exception of Northern Ireland, an embryo can be legally aborted up to 24 weeks of pregnancy. After this, it is thought to be a viable life and has full rights.
However, many people hold the opinion that an embryo of any age has the same status as any human being as life begins at conception.
A key question regarding the status of the embryo is when does a person become a person?
The Roman Catholic Church teaches that life begins at conception. However, some Christians disagree with this. One reason is that large numbers of embryos, possibly up to 50%, naturally fail to implant and are discarded naturally. Therefore, it is not acceptable to give rights to something that may not last longer than a few days or weeks.