Are they really getting "dumber"?

[epernat]

I have four kids (so far). It just seems like each child is slightly slower to learn than the one before! My DD is very smart and she likes to learn, no problem there! The next one in line is high needs, so really, I don't expect him to sit dowm and learn how to correctly form the letters and he is only slightly behind his peers which is typical for his mentality. Then comes the third DS. He talks, but not very many words and it is impossible for anyone to understand him even though he's almost three, he guesses at his colors, has no idea about letters, can only count to three etc. I know that he isn't too far behind, but the other two were far beyond him at his age, is there hope for the 3mo old? Do you think that it's because I don't have the time to teach them like I did with only one or two? My unhelpful and trying to be funny DH said it's because I'm getting older and my eggs aren't as good! Do others with many children experiance this as well? I am really getting worried!