2 Chronicles 11:18, according to the Masoretic Text, says that Rehoboam took as wife Mahalath, the son of Jerimoth, the son of David. What we have here is an obvious textual error, where the original בת "daughter" was accidentally changed to בן "son" by a thoughtless scribe under the influence of the far more numerous genealogical statements regarding men in the OT. The Masoretes recognized this error in the written text of their manuscripts and corrected it with the proper "daughter" in the margins as a Qere reading. There are only a few medieval MT manuscripts which have "daughter" in the text itself. This gives me the opportunity to make a few points:
1) Sometimes common sense is the biggest help in evaluating the textual tradition. Here it is clear that Rehoboam's wife was not David's grandson. There is no need to defend the factually incorrect consonantal text of MT with some sort of awkward gender-neutral use of "son" contrary to convention (see even the end of the same verse which uses "daughter"). Textual corruption is far more likely.
2) The more difficult reading is not always to be preferred. If it is corrupt, it should be rejected.
3) The Qere (marginal notes to be read) often provides textual variants superior to the Kethib (the consonantal text written by the scribes).
4) The fact that the medieval manuscripts so strongly support the obviously corrupt reading may indicate that they all stem from a very restricted pool of parent manuscripts. This error is unlikely to have be made so broadly across the manuscript tradition unless it traced back to a very small pool of erroneous texts.