1.   All cells possess a gene, known as the telomerase gene, which can restore the telomeres to their youthful length.

2.   But it is active in egg and sperm cells, where it maintains the telomeres at youthful length.

3.   Rather, the hope is to develop drugs that will switch on telomerase temporarily, just long enough for it to rebuild the telomeres back to their youthful length.

4.   Tests showed that the treated cells, which were middle-aged when given the gene, had quickly built back their telomerase to youthful length.

5.   The cells quickly built up their telomeres to youthful length.

6.   Their discussions focused on telomerase, the enzyme cells use to maintain telomeres at youthful length in egg and sperm cells.

7.   They have conducted tests showing that treated cells, which were middle-aged when given the telomerase gene, quickly built back their telomerase to youthful length.