I dunno. Are good genetics exactly equivalent to physical appearance?
What if that absolutely drop-dead gorgeous blonde is a hemophiliac (i.e. quite likely to die in child-birth without major medical intervention)?
What if she's color-blind to boot (hint: your sons are guaranteed to be colorblind, and vulnerable driving in locales with eccentric/horizontal-positioning approaches to stoplight placement)?
What if she is... er... "blonde"? Is it better genetics to be beautiful than intelligent? Beautiful than resistant (to diseases)?