Possible Clues:

• Bred in sin, set out this indication of it?
• No sign of a legitimate babe in arms
• Sign of bastardy on a coat of arms
• Bred in sin, set about showing one's pedigree?
• Is the Russian novel taking a turn to the left?
• Bow left mark on shield
• Nabakov's work taking ominous turn?
• Heraldic sign of illegitimacy
• British resident unhappily admitting wickedness: indication of illegitimate child
• Supposed heraldic sign of bastardy