A few points here.
Firstly, I imagine the idea was for this to be done to adults, not children. Adults tend to have developed as much as they're going to, and it takes more to damage their minds.
The last "sexual problem" is hardly a problem, it's simply not that person's cup of tea. And if that is the criteria, then I put it to you that sex involving any number of men is a sexual problem. I look forward to the day where that is the case.
Not to mention that there seem to be more cases of sexual problems these days than there were back when it was the norm, barring the raping-sprees performed by knights and others trained to be violent and self-important.
And I love the "studies that show corporal punishment is no more effective than other forms." I don't actually support it, partly because I think it should remain the pastime of consenting adults and partly because allowing a blanket "this will work, do it." isn't a good idea, considering how different people react differently to different things. However, those studies always seem to rely on faulty data:
A child is well-behaved for the most part and there is no problem: not taken to any kind of counselling, not included in data.
A child tends to misbehave, and some other punishment is used, and is successful - perhaps they hate to disappoint, and being reprimanded works well, or perhaps taking away their (item) works: chances are, they are not reported or anything, so are not included in data.
A child tends to misbehave, and corporal punishment is used, and is successful (and not abusive): again, they are not included in the data.
A child misbehaves frequently and one method is tried unsuccessfully: if the parents have sense, they'll try a number of different things before running off for help. It is here that the data is included - where all the methods attempted have proven unsuccessful.
Now, if they have a better way of gathering data, one that takes into account the cases where various methods have proved successful, that will actually be relevant and useful.
I know I have, in general, made a pretty piss-poor argument for corporal punishment of children. If I thought it was a good idea, I'd probably make a better argument. As it is, I'm surprised I managed as much as I did. The moral of the story: faulty data leads to all kinds of BS.