History of chemistry quantum mechanics were able to predict qualitatively some chemical features for biologically relevant molecules, they were, till the end of the 20th century, more a collection of rules, observations, and recipes than rigorous ab initio quantitative methods. This heuristic approach triumphed in 1953 when James Watson and Francis Crick deduced the double helical structure of DNA by constructing models constrained by and informed by the knowledge of the chemistry of the constituent parts and the X-ray diffraction patterns obtained by Rosalind Franklin. This discovery lead to an explosion of research into the biochemistry of life. In the same year, the
Rosalind Franklin analysis was often ignored because of perceived feminist overtones in her book. Watson and Crick did not cite the X-ray diffraction work of Wilkins and Franklin in their original paper, though they admit having "been stimulated by a knowledge of the general nature of the unpublished experimental results and ideas of Dr. M. H. F. Wilkins, Dr. R. E. Franklin and their co-workers at King's College London". In fact, Watson and Crick cited no experimental data at all in support of their model. Franklin and Gosling's publication of the DNA X-ray image, in the same issue of "Nature", served as