User blog comment:B214/Question and Answers 4/@comment-5.36.157.93-20150201090933/@comment-24468758-20150201132447

Even if Issei and one of the girls (most likely Rias) had a child right now, only very few old fashioned higher ups would be displeased (if the mother was either Rias or Ravel), but no one could openly disciminate against that child because the child would have a high fame in all the factions of the alliance as the whole Gremory group plus Irina is quite famous and they are part of DxD, so they would be in danger of creating a huge uproar within the alliance.