Imitation of non-Muslims or sinful people is not permissible, and is known as tashabbuh (unlawful imitation).
The following fall under tashabbuh:
- Imitation in a distinguishing characteristic of non-Muslim group/s or sinful group/s, seeing which in an individual creates a suspicion that he/she belongs with them, is like them or commits the same acts as them. 
- Imitation in a religious practice/custom of non-Muslims. 
- Imitation in something done with the intention of copying them, even if it is not religious or exclusive to them. 
It does not include something non-religious that is in principle permissible and not regarded as a distinguishing characteristic of theirs (e.g. certain forms of dress, eating certain dishes, dining on chairs and tables, speaking different languages, using certain medications or tools, using certain modes of transport, etc.) when not practised with the intention of copying them. 
It should be kept in mind that the example of the Prophet (ṣallallāhu ‘alayhi wasallam) is superior in all matters. Even in matters that are not religious – like the manner of dress, sitting, eating, sleeping and so on – it is recommended as far as possible to copy the Prophet (ṣallallāhu ‘alayhi wasallam) with the intention of being more like him. 
Is hair transplantation permissible?
Hair transplantation is a form of treatment for baldness. It involves taking hair follicles from parts of the body/head and attaching it to the balding area.
Hair transplantation entails making use of detached solid parts of the human body for medical treatment which as a rule is not permissible.
Making use of a detached solid part of the human body for treatment is only permissible when the detached part is returned to its original place (e.g. a fallen tooth or a cut finger is put back in its place).
Hence, hair transplantation is not permissible as it would fall under the general impermissibility of making medical use of detached solid parts of the human body.
Bismillāhir Rahmānir Rahīm
In the following, we will address a 9-page essay authored by Sheikh Hategekimana Hassan of Botswana called, “Perspective on Trimming/Shaving beard.” Sheikh Hategekimana attempts to show that growing the beard is not a precept of religion or Sharī‘ah, but merely a recommended cultural practice inherited from Rasūlullāh (sallAllāhu ‘alayhi wasallam). He further argues that there is no sin in shaving the beard, and the widely-held notion that a person who shaves his beard should not be appointed an imam is an innovation in Islamic thought with no basis in earlier jurisprudential writings. Continue Reading