Method and means for controlling the sex of mammalian offspring and product therefor

• US 3,894,529 A
• Filed: 04/10/1969
• Issued: 07/15/1975
• Est. Priority Date: 04/10/1969
• Status: Expired due to Term

• Current Assignee: Wallace Shrimpton
• Original Assignee: Wallace Shrimpton
• Inventors: Shrimpton, Wallace
• Primary Examiner(s): Truluck, Dalton L.
• Application Number:
  US04/814,906
• Time in Patent Office: 2,287 Days
• Field of Search: 128/1 195/1.8
• US Class Current: 600/35
• CPC Class Codes: A61K 35/52 Sperm; Prostate; Seminal fluid; Leydig cells of testes

Abstract

A method of controlling the sex of mammalian offspring by separating spermatozoa into fractions having the desired sex characteristics and artificially inseminating the female to produce offspring of the desired sex. The sperm is separated by applying a buoyant force or forces to a mixture of sperm in nutrient media so that separation occurs according to density of the sperm. The nutrient media is controlled as to density characteristics and can have a uniform density gradient from top to bottom so that buoyant forces within such media are selectively applied to sperm of differing density to effect separation of the sperm and to hold sperm fractions of different density in suspended relation within the nutrient media. Substantially pure sperm fractions (having the desired male or female sex characteristics) are isolated at the top or at the bottom of a separation column for use in artificially inseminating the female. Under certain circumstances, separation of the sperm into fractions is enhanced by the application of gas pressure (positive or negative) above the mixture of sperm and nutrient media in the column.

Claims

1. In a method of controlling the sex of mammalian offspring, the steps of mixing fresh sperm with a nutrient medium;

cooling the mixture of sperm and medium to a low temperature to immobilize the sperm;

introducing the cooled mixture of sperm and medium to a separation medium in the form of a separate body of nutrient medium, at least part of said separation medium being substantially equivalent in density to the density of said mixture and having a uniform density gradient extending from a lightest density at the top to a heaviest density at the bottom;

applying buoyant forces to the sperm introduced to said separation medium tending to separate the sperm at levels of suspension within the separation medium according to individual sperm density;

separating a portion of the separation medium of known density containing a suspended sperm fraction of equivalent density and desired predetermined sex characteristics; and

artificially inseminating a female with the separated sperm fraction whereby conception occurs to produce offspring of the desired sex.

2. A method as in claim 1 wherein the fresh sperm is introduced to the separation media at an intermediate point as respects the density gradient so that less dense sperm rise to upper portions of the separation medium while more dense sperm sediment into the lower portions of the separation medium.

3. A method as iN claim 1 wherein a bottom portion of the separation medium is separated to thereby isolate a bottom sperm fraction comprising substantially pure X-sperm.

4. A method as in claim 3 wherein the separated portion of the separation medium contains less than 10 percent of the total sperm population.

5. A method as in claim 1 wherein a top portion of the separation medium is separated to thereby isolate a top sperm fraction comprising substantially pure Y-sperm.

6. A method as in claim 5 wherein the separated portion of the separation contains less than 10 percent of the total sperm population.

7. A method as in claim 1 wherein an intermediate portion of the separation medium is separated to thereby obtain a sperm fraction containing intermixed X- and Y- sperm.

8. A method as in claim 1 wherein said separation media contains at least one member of the group consisting of whole mammalian milk, cream, nonfat milk, egg yolk, dextrose, coconut cream, tomato juice, glucose, fructose, sugar alcohols, lecithin, amino acids, living body fluids and tissue extracts.

9. A method as in claim 8 wherein all portions of said separation media have a density between about 1.010 and 1.150 grams per cc when measured at 0*C.

10. A method as in claim 1 wherein said separation media has an osmolility within the range from about 276 to 280 milliosmos.

11. A method as in claim 1 wherein said separation media has a viscosity between about 2.00 to about 9.0 centipoise when measured at 0*C.

12. A method as in claim 1 wherein said sperm is a member of the group consisting of primates, cattles, pigs, sheep, rabbit, buffalo, goat and horse sperm.

13. A method as in claim 12 wherein said sperm is cattle sperm.

14. A method as in claim 12 wherein said sperm is human sperm.

15. In a method of controlling the sex of mammalian offspring the steps of mixing fresh sperm with a nutrient medium;

cooling the mixture of sperm and medium to a low temperature to immobilize the sperm;

introducing the cooled mixture of sperm and medium to a separation medium in the form of a separate body of nutrient medium, at least part of said separation medium being substantially equivalent in density to the density of said mixture and wherein the separation medium is subject to a negative gas pressure to thereby decrease the apparent density of the sperm relative to the separation medium;

applying buoyant forces to the sperm introduced to said separation medium tending to separate the sperm at levels of suspension within the separation medium according to individual sperm density;

separating a portion of the separation medium of known density containing a suspended sperm fraction of equivalent density and desired predetermined sex characteristics; and

artificially inseminating a female with the separated sperm fraction whereby conception occurs to produce offspring of the desired sex.

16. A method as in claim 15 wherein said negative gas pressure is achieved by application of a vacuum ranging up to 20 inches of mercury.

17. In a method of controlling the sex of mammalian offspring, the steps of mixing fresh sperm with a nutrient medium;

cooling the mixture of sperm and medium to a low temperature to immobilize the sperm;

introducing the cooled mixture of sperm and medium to a separation medium in the form of a separate body of nutrient medium, at least part of said separation medium being substantially equivalent in density to the density of said mixture and wherein the separation medium is subjected to a positive gas pressure to thereby increase the apparent density of the sperm relative to the separation media;

applying buoyant forces to the sperm introduced to said separation medium tending to separate the sperm at levels of suspension within the separation medium according to individual sperm density;

separating a portion of the separation medium of known density containing a suspended sperm fraction of eQuivalent density and desired predetermined sex characteristics; and

artificially inseminating a female with the separated sperm fraction whereby conception occurs to produce offspring of the desired sex.

18. In a method of separating the sperm population in an ejaculate of a mammalian male into two portions, one portion containing substantially pure X-sperm or Y-sperm, the steps of preparing a separation media from nutrient liquids, said separation media having predetermined density characteristics;

cooling the separation media to a temperature between about -5* C. to about +2* C.;

independently collecting fresh sperm and mixing the same with a nutrient medium of the same general type as said separation media;

gradually lowering the temperature of the resultant mixture of sperm and nutrient medium to a temperature between about -5*C. and about +2*C.;

introducing the mixture of sperm and nutrient medium to said separation media whereby the latter subjects the sperm to buoyant forces tending to cause separation of the sperm according to individual sperm density and wherein said separation media comprises a mixture of at least two of said nutrient liquids, said mixture of nutrient liquids being characterized by a uniform density gradient extending from a lightest density of at least 1.010 grams per cc to a heaviest density no greater than about 1.150 grams per cc, measured at 0*C;

continuing the application of said buoyant forces to the sperm in said separation media until such time as the sperm achieves a state of relative suspension in said separation media;

separating a portion of said separation media containing a suspended sperm fraction of equivalent density and desired predetermined X- or Y- sperm characteristics; and

then inseminating a female with the separated sperm fraction to achieve conception and offspring of the desired sex.

19. A method claim as in claim 18 wherein the nutrient liquids employed in preparing said separation media comprise at least one member of the group consisting of whole mammalian milk, cream, nonfat milk, egg yolk, dextrose, coconut cream, tomato juice, glucose, fructose, sugar alcohols, lecithin, amino acids, living body fluids, tissue extracts, and mixtures thereof.

20. A method as in claim 18 wherein said fresh sperm is intermixed with a nutrient medium of the character described having a density within the range of about 1.025 to 1.038 grams per cc, measured at 0*C.

21. A method as in claim 18 wherein said nutrient medium and said separation media, when measured at 0*C., each have a pH between about 6.0 and 8.0, a viscosity between about 2.00 and 9.00 centipoise, and an osmolality between about 276 and 280 milliosmos.

22. A method as in claim 18 wherein said separation media is prepared from mixtures of whole mammalian milk and its components, and said fresh sperm is likewise intermixed with a nutrient medium prepared from a mixture of whole mammalian milk and its components, said separation media having a density within the range from 1.010 to 1.150 grams per cc and said nutrient medium having a uniform density of the order of 1.028 grams per cc when measured at 0*C.

23. In a method of separating from the sperm population of an ejaculate of a mammalian male a sperm fraction containing sex chromosomes of only one type, the steps of preparing a separation media, said separation media comprising a density controlled mixture of nutrient liquids at least two of which are selected from the group consisting of whole mammalian milk, cream, nonfat milk, egg yolk, dextrose, coconut cream, tomato juice, glucose, fructose, lecithin, amino acids, living body fluids, tissue extracts and mixtures thereof, said separation media being held as a substantially vertical column and having a uniform density gradient ranging from a lightest density of the oRder of 1.010 grams per cc at the top to a heaviest density of the order of 1.150 grams per cc at the bottom, cooling said separation media to a temperature of the order of 0.8*C., collecting fresh sperm and mixing the same with a nutrient media prepared from nutrient liquids corresponding to those selected for preparation of said separation media, the density of said nutrient medium being of the order of 1.028 grams per cc, gradually cooling the intermixed sperm and nutrient medium to a temperature of the order of 0.8*C., introducing the intermixed sperm and nutrient medium to the separation media at an intermediate point as respects the density gradient and corresponding in density to that of the nutrient medium at the point of introduction, applying buoyant forces to the sperm introduced to said separation media to effect upward movement of less dense sperm and downward movement of more dense sperm as relates to the density of the separation media at the point of introduction, whereby less dense sperm rise to upper portions of the separation media while more dense sperm sediment into lower portions of the separation medium, continuing the application of said buoyant forces to the sperm to effect a suspended state of separation of the sperm according to individual sperm densities, separating a portion of the separation media containing a sperm fraction of equivalent density and desired predetermined density and sex characteristics, and inseminating a female with the separated sperm fraction to achieve conception and production of offspring of desired sex.

24. A method as in claim 23 wherein said sperm fraction is separated from the bottom of said column of separation media to obtain a substantially pure sperm fraction containing X-sperm.

25. A method as in claim 23 wherein said sperm fraction is separated from the top of said column of separation media to obtain a substantially pure sperm fraction containing Y-sperm.

26. A method as in claim 23 wherein said buoyant forces are applied for a period of from 1/2 to 24 hours.

27. A method as in claim 26 wherein said buoyant forces are applied for a period of the order of 2 1/2 hours.

28. A method as in claim 23 wherein a vacuum of the order of 15 inches of Hg is applied adjacent the top of said substantially vertical column of separation medium, to thereby decrease the apparent density of sperm within said separation medium and particularly adjacent the top of said column.