Mirror twins ...

Mirror image twins are identical twins that have small mirror-image differences. They are actually genetically identical; this means they have exactly the same DNA. They are created when the fertilised egg splits quite late (around days 9-12). Any later and twins can be co-joined.

Some parts of the body are commonly mirrored. Mirroring of appendix or heart or other internal organs is rare.

The following are examples of mirroring:

Mirror twins are opposite handed. They tend to have mirror-image dental problems. Tuft of hair on fringe are on opposite sides. People often have two different size feet; with mirror twins the opposite foot is larger. Identical twins look very similar to each other but, for mirror twins, the resemblance is even stronger if they stand facing each other (as though in a mirror) rather than side by side. Or if they face into a mirror, things start to look very confusing. Finger prints do not seem to conform to being mirror image – instead they are nearly identical (only one pair of fingers has any major difference)

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