Embryo selection is a thing. At an IVF clinic, they will always fertilize multiple eggs at once. Once the embryo has divided into eight cells, it is possible to take the eight cell and perform DNA sequencing. You can then choose the embryo that doesn't have heritable diseases (with some degree of luck).
Note that I'm not advocating for nebulous polygenic risk scores and especially not for selecting aesthetic traits but simple genetic screening for known genetic diseases.
So if you're in the kind of family that dies of cancer at 30, and make kids at 25, perspectives don't look great.
Now, not to these people shouldn't make kids but perhaps, choose a spouse whose family dies on average at 60+?
Marry "up", not "down" :)