Asking "What planted the seed?" is assuming that there was a theism into which it can be planted. Like Mediamogul I have never been a godbotherer because it was never indocrinated into me as a child. I did however have an experience that changed my atheism from something that was in the background and not a major part of my thinking, into something that assumed more importance in my life. When I moved town a few years ago, my children were at junior school (ages 6 and 8). The nearest school to my new house was a Catholic primary school. Upon inquiry I was told in no uncertain terms that the school governors would not consider my children because they had not been christened. The knowledge that my local and national tax paid to build and run this school but my children were denied access because they hadn't had the beads rattled over them made my blood boil. From that moment on I became much more active about secularism. Incidently, my children went to a very good school a little further away.
(Just for info, in the UK, religious groups are allowed to run state schools. The state pays for the construction and running of it i.e. teachers salaries, building maintenance etc. but the board of governors, comprising the vicar/priest, church elders etc. retain the power to choose which children are accepted. Naturally they mostly select those from their own church or, if there are suffficient places, perhaps children of members of another denomination - but no children of atheists unless they are desperate to fill the rolls. A common practice in the UK is for "pretend Christians" to attend their local church for the purpose of getting in with the vicar and their children into the local church school. These state financed religious schools are mostly either Church of England Anglican or Roman Catholic, but there are a handful of Muslim/Hindu ones.)
Regards
Grimesy
(Just for info, in the UK, religious groups are allowed to run state schools. The state pays for the construction and running of it i.e. teachers salaries, building maintenance etc. but the board of governors, comprising the vicar/priest, church elders etc. retain the power to choose which children are accepted. Naturally they mostly select those from their own church or, if there are suffficient places, perhaps children of members of another denomination - but no children of atheists unless they are desperate to fill the rolls. A common practice in the UK is for "pretend Christians" to attend their local church for the purpose of getting in with the vicar and their children into the local church school. These state financed religious schools are mostly either Church of England Anglican or Roman Catholic, but there are a handful of Muslim/Hindu ones.)
Regards
Grimesy