article_snippet.sent: The defective BRAC1 gene, for example, results in inherited breast and ovarian cancer.
article_snippet.sent: By repairing this gene, the resulting egg could be made healthy.
article_snippet.sent: the sperm and eggs - means such alterations can be passed on to future generations.
article_snippet.sent: meaning the changes can be passed on .
article_snippet.sent: In reality such selection can be difficult as often there is no single gene that provides a single trait and many genes have multiple functions.