the human pre - natal development dolls of the present invention take as their models stages of human development including human gametes , zygotes , blastulas , gastrulas , morulas , embryos and fetuses at times of from just prior to fertilization to a time just prior to birth . human gametes comprise a sperm and an egg or ovum , and dolls representing them are shown respectively in fig1 , 3 and 4 . these dolls are meant to clearly show a separate and distinct stage in the complete development process . fig1 and 2 show a human sperm 1 , having a detachable tail 3 , which is an aid in depicting the loss of the sperm &# 39 ; s tail after the sperm fertilizes a human ovum or egg 5 . an additional feature of the sperm doll is a piece of velcro ®- type cloth 7 that permits the depiction of a sperm becoming fastened onto an egg , when the dolls are constructed of cloth , as disclosed further below . in the next distinct stage , a zygote is the fertilized egg that has undergone one or more cycles of undifferentiated cellular reproduction , slowly taking on a spherical shape , as illustrated by the dolls in fig5 and 6 . beyond the initial zygote stage , development progresses through blastula , gastrula and morula stages , depictions of which are also part of the invention as claimed . while the differentiation between the gamete stage and the zygote stage is readily apparent , it is important to know that there is also a differentiation between the embryo and fetus stage . embryos and fetuses are differentiated by those of skill in the art such that up to eight weeks , the developing organism is classified as an embryo and after eight weeks , it is classified as a fetus . see a child is born , lennart nilsson , dell publishing , new york , 1993 at page 91 , the entire disclosure of which is incorporated herein by reference . differentiation between development stages is very important in the practice of the invention . the differentiation between the embryo and fetus stages in the dolls is critical to the education of the user of the dolls in order to teach this recognized dichotomy of development stages . in an embryo of up to day thirty - nine , the face is not generally recognizable as human . however , since one object of the invention is to provide dolls for play , stylized faces can be built - in features of dolls of the human sperm , egg and zygote , as is shown in the drawings of this specification . as can be seen in fig8 there are few features suggestive of a human at days forty to forty two of gestation , although the earliest indication suggestive of a human face develops over a continuum of days forty to forty - six of gestation . a fetal doll that can more accurately portray a human face would be an image at days forty four to forty six , as shown at fig9 . there , such features become visible as head 2 , eyes 4 , arms 6 and legs 8 . also the first faint outline of bones such as ribs 10 can be seen . by the time of the 9th week of development , as shown by the doll in fig1 , there can be seen a clearly demarcated mouth 12 and nose 14 and a bud that can be recognized as an ear 16 . although not illustrated , fingernails also appear at about this time . also at this time , well separated fingers 18 and toes 20 are present . by week 13 , as shown in fig1 , blood vessels are easily distinguished , especially in the region of the head 22 . at this time , the fetus may be sucking its thumb , which is readily achievable in the dolls of the present invention by means of articulated joints of the kind well known in the toy art . by week 20 as shown in fig1 , even eyebrows 24 are well developed . although the models for the dolls of the present invention are human gametes and embryos in various stages of development , it should be recognized that the invention is not that of a doll taken from a human in any one point of the development process , so none of the specific features of embryos at given times of development is to be taken as limiting the invention . the dolls of the present invention are preferably manufactured either of stuffed sewn cloth by methods well know to those of ordinary skill in the doll art , or elastomeric polymers that can readily take on any desired skin tone colorant . such polymers are well known to those of skill in the polymer arts , and can be easily molded or replicated into any image at any point of the development porches . alternatively , the dolls can be fabricated of soft closed cell foam - type polymers or can be constructed so as to have a cloth outer covering . alternative materials include porcelain , pewter and precious metals . for educational purposes , the dolls can be colored as previously noted , and different racial developmental features can be molded or sewn in as well . certain types of birth defects can be exemplified , as well as developmental abnormalities , such as the occurrence of siamese twins . any one of the dolls can be provided with toy doll eyes , of the type well known in the toy industry , and can be further equipped with eyelids , including those of the variety that can open and close with the motions of the doll so that the eyelids would be open when the doll is in a substantially upright position , and closed when the doll in a substantially horizontal position . the dolls can be provided with an umbilical cord , which can be permanently or removeably attached , as by use of a snap or velcro ®- like material . external genitalia can be present of absent in one or all of the dolls . the dolls can have articulated joints that can assume different fixed positions , using internal joint mechanisms well known to those of ordinary skill in the manufacture of dolls . the dolls are generally not to scale , since fetuses in the early states , like days 44 to 46 , are only about 27 millimeters from the crown of the head to the bottom of the rump . the following non - limiting manufacturing example is provided . a model is placed in proper position on a table and a molding material comprising silastic a ®, available from dow corning co . is mixed and poured over the body from the knee line to the breast line . after this material is set up to provide an initial mold , a second layer comprising silastic b ® material is poured on the initial mold to add strength , and a plaster embossed cloth is applied over the layer of silastic b to add rigidity to the thus formed initial mold . when the materials are sufficiently cured the initial mold having an open lower portion , where the model is resting on the table , is then removed from the model . the interior of this initial mold is than painted with a creamy latex coating , which when removed from the initial mold , and suitably reinforced , will serve as a hollow positive mold . this hollow mold is then shaped to provide the same proportions as those of the live model and a negative mold of plaster material , such as microstone ® is cast around the outer surface of the shaped positive latex mold while lying upon a flat base . thereafter , the latex positive mold is removed from the negative mold and the doll constructed as follows . first a skin colored natural latex rubber such as cis isoprene available from the firestone company as f4 - latex ® is mixed with a suitable catalyst dispersion material and with silicone antifoam , and in painted on the interior surfaces of the negative mold to provide a skin for the doll . then the plaster mold is painted with a bonding agent , such as a polyurethane activated coating , and a thin shoot of polyurethane foam which has been treated in a sodium hydroxide solution is placed in firm contact with the skin . a layer of polyvinyl chloride gel is deposited upon the foam sheet to simulate adipose tissue . the skin is then bonded to the foam . this example is not to be taken as limiting the invention to the above disclosed procedure , which is exemplary in nature only . while the invention has been described and illustrated with reference to certain preparative embodiments thereof , those skilled in the art will appreciate that various changes , modifications and substitutions can be made therein without departing from the spirit and scope of the invention . it is to be particularly noted that although only a relatively limited number of drawings are given to illustrate a limited number of development times before and during pregnancy , that human development is a constant process and that the invention is of dolls through a continuous range of the development process . the claims are thus not to be limited to only those discrete points in the development process actually illustrated here .
a set of dolls for educational and play purposes in the image of a human gametes and human fetuses . the doll can be provided singly to portray one particular state of human development , or multiple dolls can be provided in a variety of stages of development , to portray continual development in the fertilization stage and first through third trimesters of development .