Hi. No, sex of baby does not affect how light or dark a line of a pregnancy test is. A faint positive is indeed a positive-- if the test was looked at during the appropriate time. A line that forms after the initial window is an evaporation line--- so if you immediately had a line appear, that's a positive. If the test sat for a bit and THEN a line appeared, that's an evaporation line. Dec. 22 would be super early to have any symptoms as those usually start really appearing at 6 weeks into pregnancy (and you'd have ovulated right before then, you'd barely have had a chance to implant let alone create enough hormones for symptoms). I would wait a couple of days and take another test, making sure to read it the right way and go with that answer. good luck and please let me know if it's positive or not.