From what I understand they couldn't hold wives or touch a female member of their own family (I'm assuming this even means hugs, pecks on the cheek, etc).
Was this because they believed female attachment would weaken them and compromise their ability as renowned warriors or was it religious? Was there even a good reason at all? And if no sons were born into the order how did they go about recruitment? Was it any old serf willing to take the vows or did they have some sort of pre-requisite?
Templars are, sadly, not my area of expertise. I've a pile of books about them in my 'to read' pile but I haven't yet had time to dig into them. This means that my answer is going to be a lot more broad and generic than I would usually like, hopefully another flair can come along and fill in the gaps!
The Templars were a monastic order, although a somewhat unique one (or at least, unique at their time of founding) since they were also a militant order. They were governed by a monastic code that set the rules of life for a Templar and included in that was a vow of Celibacy. This was fairly standard for monks at the time and the Templars were modeled after monks.
I am not aware of any restriction on touching women at all among the Templars, and it doesn't sound particularly likely given the type of Christian theology they were rooted in. However, it is outside my usual expertise. Members of the Templar order couldn't marry due to the vow of celibacy. That said, some members of the Templars were married because if you were married before joining the Order your wife was still legally your wife. You weren't aloud sleep with her or live with her but that relationship still existed. How frequently this happened I'm really not an expert on, unfortunately.
Templars would aim to recruit members from the nobility, they were after all meant to be professional religious soldiers so individuals from the martial class of society were the most highly desired, but they certainly would have had to recruit from other levels of society as well. It was not uncommon for medieval nobles to become monks later in life, warfare was seen as inherently sinful and becoming a monk was a way to repent and try to ensure your place in heaven (this is kind of a vast oversimplification of medieval theology, but that's the gist). Joining the Templars presented a more appealing opportunity for many since you could take your martial skills and put them to good use while still working towards a heavenly afterlife.
Malcolm Barber's The New Knighthood is currently the definitive history of the Knight's Templar. While most any Crusading history book that goes beyond the First Crusade will cover the Templars to some degree Barber's book is the most thorough treatment of the order out there right now.