Is it possible for someone with edwards syndrome (trisomy 18) have children in the future if they live long enough?

Maybe: This is complicated. First, in most cases, there is an extra chromosome in all cells so the sperm and eggs will be genetically defective anyways & so can't create an embryo. Rarely, one can have mosaicism in which some cells have trisomy 18 - theoretically, the sex cells could have the normal 23 pairs. However, there's also anatomic problems like undescended testes in males. So the odds are low.

Wouldn't think so: Since one has never made it to puberty I think the answer is obvious.

Do not believe so.: Only 5 to 10% live past 12 months. There is the case of Elaine Fagan who lived from 1986 to 2011. She was the longest survivor of Edwards syndrome at age 25. However, it is very rare for these children to make it to adolescence. They have profound defects- I have not heard of any cases of affected children having offspring.