Arabic text
عن ابن عمر رضي الله عنهما: أَنَّ رَسُولَ اللهِ صَلَّى اللهُ عَلَيْهِ وَسَلَّمَ نَهَى عَنِ الْقَزَعِ.
Translation
Ibn ‘Umar (may Allah be pleased with him) reported: The Messenger of Allah (may Allah's peace and blessings be upon him) forbade qaza‘ (shaving part of one's head and leaving other parts unshaven).
Explanation
The Prophet (may Allah's peace and blessings be upon him) forbade shaving part of one's head and leaving other parts unshaven. This prohibition is general and applies to all males, children and adults. As for women, they should not shave their heads.
Source: HadeethEnc.com