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Paul Nelson replies:

Actually, the situation is quite the reverse. It is Haeckel's questionable drawings which have survived in textbooks and popular publications, whereas the evidence casting doubt on his "biogenetic law" lives in the primary literature, largely neglected.

The biogenetic law is not the basis of modern developmental biology. In fact, the biogenetic law was collapsing under (a) the weight of contrary evidence and (b) its impracticality as a research tool, even before the rise of the neo-Darwinian synthesis (Rasmussen 1991). In 1894, Edmund Wilson, in his lectures to the Marine Biological Laboratory at Woods Hole, held the biogenetic law primarily responsible for "the vast number of elaborate hypothetical phylogenies which confront the modern student in such bewildering confusion" (1895, p. 103). As he continued:

It is...a just ground of reproach to morphologists that their science should be burdened with such a mass of phylogenetic speculations and hypotheses, many of them mutually exclusive, in the absence of any well-defined standard of value by which to estimate their relative probability. The truth is that the search after suggestive working hypotheses in embryological morphology has too often led to a wild speculation unworthy of the name of science; and it would be small wonder if the modern student, especially after a training in the methods of the more exact sciences, should regard the whole phylogenetic aspect of morphology as a kind of pedantry unworthy of serious attention. (Wilson 1895, pp. 103-104)

Thus, by 1909, the Cambridge embryologist Adam Sedgwick, for instance, was already looking for alternatives to the biogenetic law; as he wrote:

If after 50 years of research and close examination of the facts of embryology the recapitulation theory is still without satisfactory proof, it seems desirable to take a wider sweep and to inquire whether the facts of embryology cannot be included in a larger category. (Sedgwick 1909, p. 176)

In 1922, in his critical review of the concept, Walter Garstang argued that the biogenetic law "has evoked little but controversy and confusion" (1922, p. 81). As he continued:

As it is not to the credit of science that Zoology should harbor a "law" which, like a creed, may be accepted or rejected at pleasure, and as I believe the basis of this law is demonstrably unsound, I venture to make a renewed attempt to define the points at issue. (Garstang 1922, p. 81)

Many of the founders of neo-Darwinism (e.g., August Weismann) were intellectual refugees from the magical land of recapitulationism. Others, such as William Bateson (1894), abandoned the research program of "ontogeny recapitulates phylogeny," after their initial enthusiasm, because they discovered that ontogeny did not recapitulate phylogeny in even an approximate sense, and furthermore that the "law" suffered from grave methodological defects (1894, p. 8).

The biogenetic law is false, and has been known to be so for well over a century.

For further information, see Michael Richardson et al., "There is no highly conserved stage in the vertebrates: implications for current theories of evolution and development," Anatomy and Embryology 196 (1997): 91-106.