Any agent that interferes with normal embryonic development: alcohol or thalidomide or X-rays or rubella are examples.

Roget 663: bane, curse; evil etc. 619; hurtfulness etc. (badness) 649^†; painfulness etc. (cause of pain) 830; scourge etc. (punishment) 975; damnosa hereditas [Lat.]; white elephant.    sting, fang, thorn, tang, bramble, brier, nettle.    poison, toxin; teratogen; leaven, virus venom; arsenic; antimony, tartar emetic; strychnine, nicotine; miasma, miasm^†, mephitis^†, malaria, azote^†, sewer gas; pest.    [poisonous substances, examples] Albany hemp^†, arsenious oxide, arsenious acid; bichloride of mercury; carbonic acid, carbonic gas; choke damp, corrosive sublimate, fire damp; hydrocyanic acid, cyanide, Prussic acid, hydrogen cyanide; marsh gas, nux vomica [Lat.], ratsbane^†.    [poisonous plants] hemlock, hellebore, nightshade, belladonna, henbane, aconite; banewort^†, bhang, ganja^†, hashish; Upas tree.    [list of poisonous substances] Toxline (online).    rust, worm, helminth [Med.], moth, moth and rust, fungus, mildew; dry rot; canker, cankerworm; cancer; torpedo; viper etc. (evil doer) 913; demon etc. 980.    [Science of poisons] toxicology.    ... show more

Dutch: teratogeen