by creating donor embryos from fresh donor egg and frozen thawed sperm from our sperm donors fertilisation always takes place through the natural method (by just mixing the eggs and sperm) which allows natural selection as to which sperm will fertilise the egg, provides maximal embryo quality and success rates.

Write the above sentence using proper case.
By creating donor embryos from fresh donor egg and frozen thawed sperm from our sperm donors fertilisation always takes place through the natural method (by just mixing the eggs and sperm) which allows natural selection as to which sperm will fertilise the egg, provides maximal embryo quality and success rates.