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• When embryos are produced using IVF, doctors can test the embryos to check if they have got a certain genetic disorder - this is known as pre-implantation gentic diagnosis and is especially important if there is a concern that one of the parents might carry an alleles to a genetic disorder.
• Doctors can also test fetuses in the womb for genetic disorders by testing the fluid surrounding the fetus.

ISSUES SURROUNDING GENETIC TESTING:

• the results of genetic testing may not be 100% accurate. There are often errors due to misinterpritations and the sample being contamintated. 
• if the result is positive should other family members be tetsed. Some people may prefer not to but is that far on future partners or children.
• Is it right for someone who is at risk of passing on a genetic disorder to have children? Is it fair to put them under pressure if they decide that they want to have children?
• Like most medical procedures tests carried out during pregnancy are not 100% safe - for example doing a genetic test on the fluid around a fetus may cause miscarriages.

• Genes are instructions for cells - each gene is a code for making a certain protein, some proteins are structural proteins they are part of things like skin, hair, blood and the cytoplasm. Other proteins are functional proteins for example enzymes are proteins that help with digestion.
• A gene is a short length of a chromosome - each chromosome is on very long molecule of DNA all coiled up.
• An organisms genotypes is all the genes it has - the characteristics that an organism displays is called phenotypes.
• Genes control the development of characteristics.
• They exist in different versions and each version gives a different form of characteristics. 
• The different versions of the same gene are called alleles.

• Alleles are the different versions of the same genes.
• Homozygous traits are if you have two alleles the same for that particular gene.
• Hetrozygous traits are if you have  twio different alleles for that paricular gene.

• Children get some of their alleles from each of their parents.
• This is why children look like there parents.
• So half a childs chromosomes have come from each parent. This means that every child will have a new, unique , combinationn of allelles thats why there is no two people in the world exactly the same except for identcal twins.