tag:blogger.com,1999:blog-7100452276682801125.post1986222588678754346..comments2024-02-14T06:42:21.988-06:00Comments on Context and variation: Do girls steal some of their mother’s beauty? Sex bias in parental investmentKateClancyhttp://www.blogger.com/profile/10266484364483890008noreply@blogger.comBlogger18125tag:blogger.com,1999:blog-7100452276682801125.post-48143043138156362272011-07-10T23:22:04.239-05:002011-07-10T23:22:04.239-05:00Boys are definitely easier and I believe cheaper t...Boys are definitely easier and I believe cheaper to raise. I had one of each, and my daughter was more stressing, picky, complained (still does), needy, all about me-me-me and wants and needs the best of everything and everything everyone else has.<br /><br />My son was picky with his eating, would always give in to allow my daughter to have what she wanted because "she needs more stuff", would wear what I bought as long as it fit and he fit in, name on the label or price tag was not the life or death matter of the hour.Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-7100452276682801125.post-11005800346136210052011-06-06T12:00:55.156-05:002011-06-06T12:00:55.156-05:00Hi Anon, thanks for the question. The mechanism co...Hi Anon, thanks for the question. The mechanism could be hidden somewhere in the proportion of X vs Y sperm, but like you said, I'm guessing there isn't much variation in what men produce based on their partners (though, who knows? Sounds like a dissertation to me!). As for how it relates to pre-pregnancy weight, I'm not totally certain. There are a few differences in human fetuses based on sex, regarding the amount of hCG they secrete and the rate at which they grow. Males, on average, produce less hCG than females, and they are also slightly more likely to be spontaneously aborted very early on. However, once things are established, they do tend to grow more quickly and are slightly heavier at birth. The answer is hidden in there somewhere.<br /><br />Rich, I agree with you about the variation in investment and Hrdy's take on Trivers-Willard. Right now I can't come up with any human societies with the kinds of investment patterns you're describing, but I wonder if it would make sense to look at some populations that have high sex-selective abortion rates (China, India).KateClancyhttps://www.blogger.com/profile/10266484364483890008noreply@blogger.comtag:blogger.com,1999:blog-7100452276682801125.post-50447044507049754092011-05-31T07:29:51.489-05:002011-05-31T07:29:51.489-05:00Interesting post on the sex-biased investment stuf...Interesting post on the sex-biased investment stuff. In some situations, due to cultural perceptions of "low class," you find families heavily investing in daughters at the expense of sons. This is observed in Hungarian Roma and the Mukugodo of Kenya. Daughters can "marry up" and into a higher class by marrying non-Roma or non-Mukogodo respectively. Given this, parents in these groups invest in daughters and often give little attention to the males. This is sex-biased investment but it doesn't necessarily conform to a Trivers-Willard scenario, since mother's condition doesn't really matter. <br /><br />Regarding the T-W hypothesis, I like Hrdy and van Schaik's observations (1991 Am Nat) that show how the T-W hypothesis can be reversed when dominance hierarchies and female philopatry are in place (as is often the case in many female cercopithecines). High-ranking females, who are in good condition, are biased to produce daughters, since these daughters can inherit their mother's high rank and reproduce early; however, low-ranking females, who are in poorer condition, should produce sons, since these sons can disperse and "try their luck" elsewhere. I wonder if this occurs in any human societies...probably not.rich lawlerhttp://www.propithecus-verreauxi.comnoreply@blogger.comtag:blogger.com,1999:blog-7100452276682801125.post-38443015130142557662011-05-30T17:56:30.315-05:002011-05-30T17:56:30.315-05:00I know I'm a little late to the game here, but...I know I'm a little late to the game here, but I have a question. Sex of a fetus is determined by the sperm and I tend to think that this suggests that the sex of the fetus has some probability of being XX or XY (or XXX, XXY, etc although those are much rarer) depending on the proportion of X and Y sperm that the men produces (which probability should be randomly distributed across women of all weights in the study). <br /><br />So why would pre-pregnancy heaviness correspond to producing male fetuses? <br /><br />Is the idea that because of the plenty of the environment, that female fetuses would be more likely to be spontaneously aborted at a very early stage of development? <br /><br />Or would the plenty of the environment give some advantage to the Y sperm at the expense of the X sperm?Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-7100452276682801125.post-3406959601868477552011-05-25T14:35:59.990-05:002011-05-25T14:35:59.990-05:00GPD, that's a great question but I have no ide...GPD, that's a great question but I have no idea whether they have the data to tell that! I would assume they have it, maybe in another paper that I haven't seen :).<br /><br />Most recent anon, yes, that's why it's not the best measure, but they did find a statistically significant difference between mothers of sons versus daughters. That lends at least a little credibility to the method. Variability doesn't mean you can't find a difference, and I don't think the author was asserting the sex of the fetus is the only factor.KateClancyhttps://www.blogger.com/profile/10266484364483890008noreply@blogger.comtag:blogger.com,1999:blog-7100452276682801125.post-41033798985763993852011-05-23T20:00:47.322-05:002011-05-23T20:00:47.322-05:00I would be very cautious about the breast size thi...I would be very cautious about the breast size thing. There is great variation with breast sizes before, during, and after pregnancy and also before, during, and after weight gain of any kind. I have never heard of the gender of a baby playing a role in the pregnancy portion, and it sounds way too complex to be even mainly influenced by that one factor.Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-7100452276682801125.post-33716634620312845432011-05-21T12:52:14.416-05:002011-05-21T12:52:14.416-05:00Great post.
In your first graph, how many childre...Great post.<br /><br />In your first graph, how many children (grandchildren) did the boys have and how many did the girls have? If daughters have more kids then increased lifespan of their mothers may be reflective of simple investment in ensuring their longterm fitness.<br /><br />As for breast size...I would again think in terms of long-term fitness.unknownhttps://www.blogger.com/profile/05949487275042211766noreply@blogger.comtag:blogger.com,1999:blog-7100452276682801125.post-73870394427926078992011-05-19T16:58:53.673-05:002011-05-19T16:58:53.673-05:00If it counts for anything, everyone I've ever ...If it counts for anything, everyone I've ever talked to thinks girls are _much_ easier to raise than boys . . . I've never heard of anyone saying the reverse!Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-7100452276682801125.post-74964689476337801122011-05-19T11:11:03.086-05:002011-05-19T11:11:03.086-05:00Really interesting post!
I wonder whether studies...Really interesting post!<br /><br />I wonder whether studies like these could be done in mammals who don't rely on assistance from daughters for childcare? That might help to distinguish between the cultural/adaptive and hormonal hypotheses.<br /><br />-Principle InvestigatorAnonymousnoreply@blogger.comtag:blogger.com,1999:blog-7100452276682801125.post-20260016415478079312011-05-19T09:11:00.313-05:002011-05-19T09:11:00.313-05:00Thanks GMP and praprotnik :).Thanks GMP and praprotnik :).KateClancyhttps://www.blogger.com/profile/10266484364483890008noreply@blogger.comtag:blogger.com,1999:blog-7100452276682801125.post-44501031480771933862011-05-19T07:47:03.481-05:002011-05-19T07:47:03.481-05:00Very interesting post! I really liked your mechani...Very interesting post! I really liked your mechanistic explanation.praprotnikhttps://www.blogger.com/profile/07291033748492285572noreply@blogger.comtag:blogger.com,1999:blog-7100452276682801125.post-65263120815058839572011-05-18T11:01:33.397-05:002011-05-18T11:01:33.397-05:00What a great post! Thank you.What a great post! Thank you.GMPhttps://www.blogger.com/profile/17872461021953583473noreply@blogger.comtag:blogger.com,1999:blog-7100452276682801125.post-5843617116767872722011-05-18T09:52:21.979-05:002011-05-18T09:52:21.979-05:00I'm sorry for sounding crass. I tried clicking...I'm sorry for sounding crass. I tried clicking and enlarging earlier today, and it didn't work. Now it's fine. Although I can't use the zoom-function, I have to ctrl++. I think you could probably make them larger in your post as well, though. But that's up to you.Martha Joyhttps://www.blogger.com/profile/02461330577913907626noreply@blogger.comtag:blogger.com,1999:blog-7100452276682801125.post-12658108640198841882011-05-18T08:22:09.026-05:002011-05-18T08:22:09.026-05:00Thanks, all. Matt, that might be right for particu...Thanks, all. Matt, that might be right for particular data points. The very different trend with increasing numbers of sons or daughters, though, is significant.<br /><br />Martha, I have similar concerns about the method. But Galbarczyk does show that it is a validated method, and even if there is variation based on where you get measured, likely mothers of sons and daughters would be equally off. So, that would explain why you could still find a relationship. As for the graphs: if you click on the image it does get bigger. You can also download them on to your computer to zoom in. I am sorry you find them "useless." I have to balance the appearance of the post with the size of the images.<br /><br />John, yes exactly! I'm guessing even married daughters would help in some circumstances. In general, caretaking by women happens in lots of ways. Probably having daughters eases the burden of all caretaking by the mother.KateClancyhttps://www.blogger.com/profile/10266484364483890008noreply@blogger.comtag:blogger.com,1999:blog-7100452276682801125.post-21977380644630963962011-05-18T08:08:23.649-05:002011-05-18T08:08:23.649-05:00It may be that unmarried daughters, in some times ...It may be that unmarried daughters, in some times and places, could be depended upon to care for elderly parents. Daughters-in-law, too, of course (I'm thinking of Japan). Hence, contributing to longevity of the parent(s).John McVeyhttps://www.blogger.com/profile/14481670714832899230noreply@blogger.comtag:blogger.com,1999:blog-7100452276682801125.post-13360857100071426892011-05-18T05:57:25.151-05:002011-05-18T05:57:25.151-05:00My first thought about bra sizes: That's not o...My first thought about bra sizes: That's not objective. I have changed my bra size considerably when I changed shops, even though I have not lost or gained weight. I have used both 85C and 65F in the same month. But the 65F fit better.<br /><br />The image of the Indian family makes me cringe. <br /><br />Your graphs are very hard to read, and I can't make them bigger on my screen. They're blurred and useless, sorry. Something you can do about that?Martha Joyhttps://www.blogger.com/profile/02461330577913907626noreply@blogger.comtag:blogger.com,1999:blog-7100452276682801125.post-12910853972472638752011-05-18T05:20:23.410-05:002011-05-18T05:20:23.410-05:00Kate
Excellent piece.
I was wondering tho ... fo...Kate <br />Excellent piece. <br />I was wondering tho ... for our culture with the lower number of children per mother, isn't the students' answer correct. Looking at the data, for say 2 sons and 2 daughters, the mother has a longer life expectancy for having 2 boys (74 years vs 72 years).Matthttp://sciencegeist.netnoreply@blogger.comtag:blogger.com,1999:blog-7100452276682801125.post-47693121500302209712011-05-17T23:09:06.812-05:002011-05-17T23:09:06.812-05:00Very interesting; I enjoyed reading this.
-Rainee...Very interesting; I enjoyed reading this.<br /><br />-RaineeAnonymousnoreply@blogger.com