Can legitimised bastards be heirs?

I'm the petty king of Munster. I have a daughter by my ex-wife and my new wife isn't very fertile. I gave a courtier a good tumble, she gave me a son, and I legitimised him.

I was expecting the legitimate bastard to then become the heir - however, my daughter is still the heir. I'd really like to make my son the heir, to get rid of the "female heir" negative opinion from my vassals. Why did this happen?

N.B. - My son is considered "my son", he is of my dynasty.

A legitimized bastard becomes a permanent member of the dynasty of the legitimizing parent, and is allowed to inherit from both parents. (source)

There are still a few reasons which may prevent your son from becoming, when his time comes, the Petty King of Munster (source):

• being a member of the Clergy
• having taken the vows and become a monk
• being a member of a Holy Order
• having been castrated (ouch !). No balls, no crown.