My comment about separating the sexes was to avoid an unplanned pregnancy. I wasn't suggesting that there was more risk of boar taint with a mixed group.
Mine are nearly always in mixed groups, but I do tend to separate at five months.
As I said, I've not had a problem with traditional breeds. The only time I experienced it was with a group of Pietrain x Landrace pigs which I kept to about six or seven months.