“Miller's experiment could be replicated by a 12 year-old. The reason for the careful controls is not that careful controls are necessary for the reactions to take place, but that controls are necessary to rule out contamination as the source of the products.”
From part 1 of the article:
Many carbon-based molecules have a property called ‘chirality’— they can exist in two forms that are mirror images of each other (like our left and right hands) called ‘enantiomers’. Living organisms generally use only one of these enantiomers (e.g. left-handed amino acids and right-handed sugars). In contrast, naturalistic experiments that produce amino acids and sugars always produce an approximately 50:50 mixture (called a ‘racemic’ mixture) of the left- and right-handed forms. The horrors of the thalidomide drug disaster resulted from this problem of chirality. The homochiral form of one kind had therapeutic benefits for pregnant women, but the other form caused shocking fetal abnormalities.
From part 2:
The ground level of the autopoietic hierarchy is perfectly pure components, such as only left-handed amino acids (in contrast to the dirty chemistry of the natural environment). De Duve has no naturalistic explanation for this transition because the mass-action laws of environmental chemistry drive it towards mixtures rather than purity.
The Miller experiment creates a racemic soup of left- and right-handed enantiomers that would be toxic to life.