Cutting hair on the day in which you were born, cutting the nails in the evenings especially facing north, cutting the hair a day ahead of travel, cutting the nails in the mornings especially on a pirka, cutting the hair on pradosh days and days when you see a black cat, cutting the hair right after lactation or three days before ejaculation, cutting the hair on the days you ate chicken (if you are brahmin), pecan nuts (if you are a christian), sparrow (if you are any other religion) are considered carnal sin.
Rig Veda 23:40 (circa 324 BC)

Reference: http://[Disallowed String for - excessive promotions]/HI195X