生理特征（如人脸、虹膜、指纹、掌纹、声音等）与生俱来，多为先天的；行为特征（如步态、笔迹等）则是习惯使然，多为后天的。
Physiological characteristics , such as face , iris , fingerprint , palmprint , voice etc. are connatural , whereas behavioral characteristics which are the habits of human , such as gait , handwriting , are postnatal .
先天行为