Bilateral symmetry is pretty much an essential for me when selecting a girl. Fortunately it's also pretty common. So much so that I never really feel obliged to comment on it.
Picasso may have been a great painter, but I've never much fancied any of his girls...
common in that people are generally not very lopsided.
Look carefully though and you will usually find some asymmetry, often one foot or hand is larger than the other, one bollock hangs a bit lower
quite a few people have one leg longer then the other, one breast a little lower, one a little smaller.
Me, i'm a positive determinist and just take them as they come and add them to my "stamp/pussy collection"