This article from last October addresses the issue, and though certainly not conclusive, does raise some interesting points:
liturgyguy.com/2013/10/06/altar-boys-and-the-priesthood/
It most certainly is not conclusive. There is so much information that is not addressed in the study, that it is hard to know where to begin. Note: I am a strong supporter of CARA.
How many of them attended Catholic college/ How many Catholic high school? How many Catholic grade school? How many a combination of the above?
What size of families? What age did they start seminary?
Do those statistics vary much from, say, the statistics of 1964 (if there were any)? 1954? 1944?
Out of the number of women who have joined an order of sisters or nuns, how many of them were altar servers? And etc. of all of the above questions?
How many (of either men or women) were from families of three or more children? And this is just scratching the surface.
What effect is secularism playing in the reduction of the numbers of vocations? Careerism? Why are the majority of vocations later in life? What factors play into the delay? Again, just a few of the questions that need to be asked.
Unfortunately I don’t think there have been any thorough studies on the subject, though you would think with the continuing priest shortage we are facing, the Church would take the time and money to fund this kind of research.
Speaking from personal experience, I know of families who have young boys that do not want to serve at their parish because the parish predominantly has altar girls, and at that age, boys generally want to be around other boys. Whether or not this will hinder the boys’ desires to become priests, who knows.
This card keeps being played. We also had more Catholic schools 50 years ago. And the issue is simply a matter of parenting. We have far too few parents with enough backbone to make the decisions, instead of rolling over and letting a 6th or 7th grader make them.
I do know that our parish (of about 250-300 families) has recently had 2 ordinations to the priesthood, 2 enter the convent, 3 currently enrolled in seminary, and 3 in monastic life. I belong to an EF parish that only has altar boys. Again, this is not conclusive, just personal experience.
And I belong to an OF parish that has produced 2 deacons and a third candidate who has just finished his Masters: at least three priests, a seminarian who decided this was not his calling, and a professed sister in what is considered a “conservative” order (identifiable habit). And she was an alter server.
There are a multitude of issues at play as to why there have been a reduction in vocations; it is simplistic to point at who serves and attempt to show that is the cause of the reduction. Which is not to say that it has or has not any impact. Only that as it stands, it is not much better than post hoc, ergo propter hoc.
Your experience is unusual; and the question is, what other factors are at play in the matter?