Mrsruffallo, that's a bit disingenuous to be fair.
I work closely with child psychologists and am a speech and language therapist. I don't deny any of the arguments and I think some certainly have validity. The idea of leaving my child in formal daycare (regardless of type or quality) is very distressing to me yet for me - as for many others - paying the mortgage (on my modest 2-bed ex council house) means I really do need to return to work.
I can see both sides of this argument but I disagree with research being poorly summarised and allowing for the extrapolation of Grand Arguments. There isn't a sufficient body of evidence regarding, say, so-called "dosage" of daycare.
I personally feel, probably, full-time daycare away from both parents (and I stress parents here, vs mothers) for perhaps 50 hours a week might in daycare of questionable quality is probably going to have a negative impact. Yet no distinction is made between this pattern of daycare attendance and say, mornings only/four mornings a week/2 days a week etc etc, or between the SAHM stressed and in poverty with 2-3 kids under 3 vs the part-time working mother with one child in a secure home environment who is financially stable etc etc. The variables are endless and unaccounted for in the research, as yet.
The 'SAHM is best' argument seems to ignore the obvious: for every yummy SAHM living in a leafy suburban area taking Junior to the Mums and Toddlers at the local church and feeding the ducks at the park on endless sunny afternoons, there is a SAHM living in an unstable and chaotic home where interaction involves them cutting the off 'shut up', 'give it a rest' etc on a more or less constant basis, saying no to everything they ask, leaving them strapped in a buggy with a dummy in their mouth in front of the TV.
This is a feminist issue and a class issue combined, let's face it.