1. Introduction
2. The Right to Procreate
  2.1 Skinner v. Okla.
  2.2 Wiscon. v. Oakley
  2.3 Involuntary Sterilization
  2.4 Kin Selection
  2.5 Marriage
  2.5.1 Anonymous
  2.5.2 Tompkins v. Tompkins
  2.5.3 Williams v. Williams
  2.6 Transgender Marriage
  2.7 Polygamy
  2.8 Prostitution
  In Brief
3. Who Is My Family?
3.1 Family Identity and the Right to Associate with Kin
  3.2 Marriage and the Paternity Presumption
  3.2.1 Jones v. Trojak
  3.2.2 Michael H. v. Gerald D.
  3.2.3 William "TT" v. Siobhan "HH"
3.3 Paternity Estoppel
3.4 Equitable Parenthood
3.5 Duty to Support
  3.6 The Paramour Statute
  3.7 Maternal Transmission of Citizenship
  In Brief
4. Whose Child Is This?
  4.1 The Surrogate Cases
  4.1.1 Johnson v. Calvert
  4.1.2 Belsito v. Clark
  4.2 Shotgun Weddings
  4.2.1 Fairchild v. Fairchild
  4.2.2 Gard v. Gard
  4.2.3 B. v. S.
  In Brief
5. Shopping For Eggs & Sperm
  5.1 Bad Sperm
  5.2 Cryogenic Orphans & Waifs
  5.2.1 Gifts of Sperm
  5.2.2 Who Is My Father?
  In Brief
6. Sexual Orientation
  6.1 The Right to Practice One’s Sexual Orientation
  6.2 Discriminating on the Basis of Sexual Orientation
6.3 Same-sex Adoption
6.4 Same-sex Marriages
  In Brief

2.4.  Kin Selection

From an evolutionary perspective, the objective of reproduction is to propagate one’s genes.  Personal reproduction is one way to achieve this.  Another is to help individuals who share the same genes.  Similar genes are present not in only in offspring and their parents, but in other relatives, as well.  A mathematical way of representing the probability that any two relatives share the same genes is called the “coefficient of relatedness” or r.  Between parent and offspring, r is 0.5; between full siblings, 0.5; between uncle/aunt and nephew/niece, 0.25; between grandparent and grandchild, 0.25; and between cousins, 0.125.  Animal Behavior, by J. Alcock, Sinauer Associates, Fifth Edition, 1993, Pages 506-510.  Say an individual had the choice of producing a single offspring or foregoing reproduction to raise his sister’s three children.  The r value for his own child is 1 x r (1 x 0.5) or 0.5, but for fostering his nieces and nephews it is 3 x r (3 x 0.25) or 0.75.  In other words, it is evolutionarily more profitable for him to relinquish his procreative potential in favor of raising his relatives.  The theory that individuals may assist their kin to promote the maximum propagation of their genes is called “kin-selection.”

Consider the following case:  William E. Story, Sr. was the uncle of William E. Story, 2d.  Uncle Bill promised his nephew Willie that if he would refrain from drinking, using tobacco, swearing, and playing cards or billiards for money, until he became 21 years of age, he would pay him the sum of $5,000.  On his 21st birthday, Willie wrote to his uncle, informing him that he had performed his part of the agreement, thereby becoming entitled to the $5,000.  The uncle agreed, but suggested that Willie leave the sum of money in a bank account with him. “Now Willie, I do not intend to interfere with this money in any way till I think you are capable of taking care of it, and the sooner that time comes the better it will please me.  I would hate very much to have you start out in some adventure you thought all right and lose the money in one year.” Willie took his uncle’s advice, leaving the money with Uncle Bill.  The uncle died several years later without turning over any of the money to Willie.  Eventually, Willie sold the right to the money to a third-party, who brought an action against the executor of Uncle Bill’s estate for the $5,000.  Hamer v. Sidway, 124 N.Y. 538, 27 N.E. 256 (Court of Appeals of New York, 1891).

Should the court enforce the contract, and turn over the money to Willie?  The general rule is that a contract which lacks a bargained for exchange of value, referred to as “consideration,” will not be enforced. Consideration serves several useful purposes.  It provides an evidentiary function by furnishing evidence that a binding contract exists.  It also serves a deterrent function against rash, impulsive actions.  Consideration helps to prevent an unreasonable promise, such as a joke, from being performed to the detriment of the promisor.  Contract Law and Theory, by R.E. Scott and D.L. Leslie, The Mitchie Company, 1988, Page 121.  Willie certainly had been promised something of value to him, $5,000.  This motivated him to perform his part of the bargain.  But what Uncle Bill?  What benefit was Willie’s performance to him? 

Notwithstanding Bill’s moral satisfaction from Willie’s forbearance, let’s assume that Bill received nothing of tangible value.  If so, the contract should not be enforced because there was no consideration.  Maybe what really happened is this:  Seeing Willie with a cigar in his mouth and a glassful of Scotch in his hand, Bill jokingly offered to give him $5,000 if he gave up smoking and drinking.  Of course, Bill never intended for Willie to accept his offer.  He knew that Willie loved the wild life too much.  Wouldn’t he have asked for something valuable in return, if he had really meant it? “If you forbear tobacco and alcohol for the next five years, and turn over your wine and cigar collection to me, I’ll give you $5,000.”

Let’s say that Willie is Bill’s nephew.  Is consideration still necessary?  Kin-selection theory identifies a basis to enforce the promise.  Any benefit to Willie accrues to Bill, as well, since Willie is genetically part-Bill.  (Coefficient of relatedness is 0.25).  Thus, Bill’s promise of $5,000 to Willie is valuable to Bill, as well, to the fraction of genes in Willie that Bill shares.  Giving money to Willie is a way of promoting the maximum propagation of Bill’s genes.  Kin-selection is a substitute for consideration