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In this section, I briefly explain two important distinctions. First,‘selective reproduction’ (as

I use the term here) can cover both choicesbetween different possible future children and

decisions about how many children to have (if any). Choices of the latter kind have been

termed different number (because we are choosing between one number of children and

another) while those of the former kind are calledsame number (because we are choosing

not how many but rather which possible future children to create).1 The same number

versus different number distinction is often theoretically and ethically important but is rarely clear-cut when it comes to questions of policy. This is because many policy decisions

affect both who comes to exist and how many people come to exist: both the constitution

and the size of the future population. For instance, vigorously discouraging teenage

pregnancy may well result indifferent children being born, but also in fewer children being

born.

The second, more complicated, distinction is between choices that areidentity-affecting

and those that are not. Some choicesalter the characteristics of a determinate future person

(making someone more or less healthy, for example) whereas others amount tochoosing

1 _{This terminology originates in Parfit’s seminal work, Reasons and Persons. He writes: ‘Different}

Number Choices affect both the number and the identities of future people. Same Number Choices affect the identities of future people, but do not affect their number. Same People Choices affect neither’ (Parfit, 1984: 356).

between the creation of distinct possible future persons (choosing a healthier one over one with a genetic disorder, for example). Selective reproduction (or at least the kind of selective reproduction that is the subject of this chapter) involves the latter rather than the former.

The choices that we make when we practise selective reproduction are identity-affecting.

They are alsoexistential, causing people to exist who otherwise would not, or preventing the

creation of (possible future) people. To make this distinction clearer, think about the following actions or policies:

Vaccinating infants Encouraging breast feeding

Discouraging smoking and drinking during pregnancy ---

Discouraging teenage pregnancy

Preimplantation genetic diagnosis (PGD) and embryo selection Sperm sorting for sex selection

Having‘unprotected’ sex with numerous MENSA members (for reproductive purposes)

rather than one’s intellectually mediocre husband.

The first set of policies are not (or at least not directly or intentionally) identity-affecting. These policies, if successful, would lead not to the creation of different possible future people but rather to improvements in the health and longevity of people (or foetuses) who already exist, or whose future existence is not dependent on the action or policy in question.

Of course, even these policies may have indirect effects that are identity-affecting or

existential, affecting which (possible future) people come to exist and/or whether certain (possible future) people come to exist. Take the following case, for example:

Grace, a young woman, smokes and drinks heavily during pregnancy. Tragically, as a result of this behaviour, Grace’s baby, Olivia, dies during infancy. A year later Grace proceeds to have another child, Jack, who is in good health. Grace is certain that, had it not been for Olivia’s death, she would not have had Jack.

If the population contains a number of women like Grace, it is safe to assume that implementing policies that discourage smoking during pregnancy will have identity- affecting side-effects. They will lead to the survival of babies like Olivia (which is not, considered in itself, identity-affecting) but also to the non-conception of (possible future) babies like Jack (an existential effect). But at least we can say of the policies in the first group that, while they may indirectly affect who comes to exist, this is not their main aim.

The actions and policies in the second group, conversely, are directly identity-affecting and altering the constitution of the future population is part of their aim (although those involved may not conceptualize it in quite these terms). These policies determine which (possible future) people will come to exist. For example, if we successfully encourage prospective teenage mothers to delay their pregnancies by ten years then we are getting

them to havedifferent children from the ones they would otherwise have had (and/or to

have fewer children). When, following PGD, we choose between embryos for possible implantation we are choosing between one (possible future) child and others. When we separate X-chromosome sperm from Y-chromosome sperm and choose to use one or the other for sex selection, we are choosing between different (possible future) children and

who is inseminated by MENSA members, rather than her husband: she is choosing to have a different (possible future) child.

Why do we generally regard such policies as identity-affecting? It may be because we

accept what Parfit calls theTime-Dependence Claim:

If any particular person had not been conceived within a month of the time when he was in fact conceived, he would in fact never have existed.

(Parfit, 1984: 352)

However, this looks less credible than when his Reasons and Persons was first published

because of the possibility of freezing and later using gametes. So perhaps what Parfit calls

theOrigin View is what underpins these intuitions about identity:

. . . each person has this distinctive necessary property: that of having grown from the particular pair of cells from which this person in fact grew.

(Parfit, 1984: 352)

According to the Origin View, coming from the particular sperm and the particular ovum

from which I in fact originate is anecessary condition for something’s being me. So, if those

particular gametes had never existed, or if a different sperm had got to that egg first, then I would never have existed. A different (numerically distinct) person would have come to be instead.

In the case of preimplantation genetic diagnosis and embryo selection (anda fortiori in

the case of selective abortion) there may be an additional reason for regarding selective reproduction as identity-affecting. In principle, each of the available embryos could be implanted and become a person (Embryo A would become Person A, Embryo B would become Person B, Embryo C would become Person C, etc.). And it seems to follow that, just as we could decide to implant them all and thereby create A, B and C, so we can choose between (possible future) Person A and Person C, by choosing between Embryo A and Embryo C. Perhaps one of the main underlying thoughts in the embryo selection case is simply that Embryo A and Embryo C are distinct organisms, spatially distinct

physical objects. Thus Person C, qua Adult Body C, could not have been Embryo

A because Embryo A and Adult Body C lack physical spatio-temporal continuity (whereas

Adult Body C and Embryo C are spatio-temporally continuous). Two things (or ‘thing-

stages’) are ‘spatio-temporally continuous’, in this sense, if they are connected by a

continuous path through space-time; spatio-temporal continuity is widely regarded as being essential to the identity or persistence of physical objects over time.

Something like the Origin View (which we may also term gametic essentialism)

appears to be the bioethics orthodoxy, but it is not entirely uncontroversial and has been questioned by some scholars (Wrigley, 2006). However, even if we were to eschew a fully fledged gametic essentialism (and to accept, for example, that there is a possible

world in which I‘came from’ a different spermatozoon) we could nonetheless retain the

view that embryo selection (and a fortiori foetus selection) involve choosing between

different numerically distinct (possible future) persons. This is because of the point just made: that in such cases we are choosing between existent spatio-temporally distinct physical objects. So since practices of this kind are my main concern in the rest of this chapter, it is safe to assume (for the present purposes) that selective reproduction is identity-affecting.

The main reason for dwelling on the fact that selective reproduction is identity-affecting is that this has implications for the way in which the ideas of benefit and harm can be applied. For example, say we have a choice between bringing into existence:

RUBY: a (possible future) healthy child, and –

EMILY: a different (possible future) child with a genetic disorder, Z Syndrome; and that, according to existing people with Z Syndrome, it is extremely debilitating and painful but consistent with living a fulfilling and worthwhile life.

If we choose to create Ruby, who will have been benefited and who will have been harmed (leaving aside for the present the interests of third parties, such as parents and the National Health Service)? Arguably Ruby benefits, but the benefit for her is existential,

the‘gift of existence’; crucially, it is not being born without Z Syndrome, because the choice

facing us was notRuby with or without Z Syndrome, rather it was Ruby or Emily. Of course,

Ruby might feel glad not to haveZ Syndrome and is better off than she would be if she had

Z Syndrome, but this is true of all healthy children, not just selected ones. Turning now to Emily, she does not appear to benefit at all, both because she does not exist and because (even if we can make sense of non-existence being beneficial) her life, had it existed, would

have been worth living and of some positive value to her. Has Emily beenharmed by the

decision to select Ruby? Probably we would say‘no’ because of the problematic (arguably

absurd) implications of allowing the idea that we harm amerely possible future person when

we fail to bring her into existence.

What if we had chosen Emily instead? Similar considerations apply. If Emily has a worthwhile life overall we might say she had been benefited existentially (just as Ruby would have been if she had been chosen). And, while she would be better off without Z Syndrome (in that sense, it is a harmful condition), creating Emily has not harmed her because she would not be better off not existing. As for Ruby, we probably want to say (as we did of Emily in the previous scenario) that her non-existence neither benefits nor harms her (Table 3.1).

The relevance of this is that often, when practising selective reproduction, while there is an overall welfare gain (because of the absence of disease), there may be no particular individual who benefits (or is protected from harm) in any straightforward way because the welfare gain is distributed across different possible populations.