Why do Christians become Christians?

[TubbyTubby]

So what is adult conversion to Islam based on, with 2) as the given?

It's clearly not the message when it doesn't seem to matter what the message is. It's the help. Come for the food and medicine, stay for the religion.

http://www.pewresearch.org/fact-tank/201...ous-group/

The main reasons for Islam’s growth ultimately involve simple demographics. To begin with, Muslims have more children than members of the seven other major religious groups analyzed in the study. Each Muslim woman has an average of 3.1 children, significantly above the next-highest group (Christians at 2.7) and the average of all non-Muslims (2.3). In all major regions where there is a sizable Muslim population, Muslim fertility exceeds non-Muslim fertility.

The growth of the Muslim population also is helped by the fact that Muslims have the youngest median age (23 in 2010) of all major religious groups, seven years younger than the median age of non-Muslims (30). A larger share of Muslims will soon be at the point in their lives when people begin having children. This, combined with high fertility rates, will accelerate Muslim population growth.

Do you a link that shows data on adult conversions to Islam?

You are probably right--a bias will form. Is your assertion that faith is a direct result of locale and upbringing? That does not make sense if at least 15% of Christians (in the US) become so as adults nor does it explain the tremendous growth of Christianity in Africa and China (which would presumably be a much higher rate of adult conversion. 

It seem like more of an opinion rather than a fact that Christians should just "accept".

So Islam growth is caused by parents/indoctrination/locale but christians are a bit more discerning?