@Lweji - As I said earlier, I got a preview when it was being peer* reviewed ie. it is not published. I realise that this could easily sound like I made up the work but that's the thing about an anonymous chat forum... you have to decide what you believe. I realised earlier I said, 'log on'. I meant to my google docs to check a few facts like age of the babies tested.
Of course, they may be huge flaws in the work which mean it's never published in a respected journal.
You'll have to trust me. If you don't I will be PM'ing you at sometime in the future having hunted for permission to prove an anonymous woman on the internet 'wrong' 
Surely it's not the only one.
There are lots.
PNAS
"Analysis of these changes developmentally demonstrated differences in trajectory between males and females mainly in adolescence and in adulthood. Overall, the results suggest that male brains are structured to facilitate connectivity between perception and coordinated action, whereas female brains are designed to facilitate communication between analytical and intuitive processing modes."
Not babies, but this spoke about the changes when our children have already been ruined through gendering (according to some). The account for delay appears to be biological.
Sex Differences in the Brain
"On average, there are likely to be some areas that are more strongly feminized in a female and others that are more strongly masculinized in a male, but averages are never predictive of an individual’s profile. Moreover, a mosaic is not a blend—there is not a continuum of maleness to femaleness—and there are many parameters that are neutral in regard to sex, with no consistent differences between males and females."
These studies cannot eliminate the nature / nurture argument and no ethical experiment truly can, from my limited understanding.
@SaskiaRembrandtWasFramed
What I'm saying is, there are far too many people who don't conform to the concept that they can't be described as random anomalies or statistical outliers.
Are there? Link?
suggest it is would be due to either bad analysis of the data
I'm not a statistician- (beyond a hard-won O Level). I understand the basics but if you can explain to a layman why these are all incorrect, I'd appreciate it.
Also, [no sarcasm], you seem extremely sure that these stats are being interpreted poorly or willfully misused. Not many scientists have come out as firmly in either nature or nurture camp and it's very much up in the air with theories being explored.
Doesn't the quote from the second article explain why there can be so much overlap or difference or 'non-conformity.
*I'm not a peer. It's well beyond my area of expertise.