Your baby at nine months

At nine months your baby will have discovered what it means to be mobile (although some babies are resistant to going anywhere and are happy to stay sitting). She'll be fine-tuning her hand and eye co-ordination and also her social skills. She will howl the house down if you hand her over to someone she has never met before.

Her physical achievements: She has mastered sitting, managing ten minutes without cushions to prop her up. She can reach forward and grasp things without collapsing face forward onto the floor. She may be able to take her weight on her legs and cling on to the furniture. Some babies can 'cruise' around, shuffling while holding onto something.

She can finally hand something to you, rather than hold it out to you and stand there wondering what she has to do to let the wretched thing go. But best not to take things off her, as she will scream. She may learn to clap, especially if you show her how to, and this is a nice party trick for relatives and more predictably successful than bye bye (there's often a time delay here which means she's managed to wave just after they've driven off). she may be able to make her first brick tower - two blocks, which will wobble alarmingly but fill your heart with pride. If you gently throw a ball to her (best not to let Dad do this, as gently throwing a ball is not a male concept) she may gather it up, which in my book counts as a catch.

Her ability to transfer objects between her hands is good and she will use a palmer grip - the palm of her hand and her fingers will close over something - a more advanced technique than the grasp. In the strive towards manual sophistication she will move her thumb to oppose her fingers. She can now pick up peas and small bits of bread to eat. She may also start to hold a crayon, but is more likely to chew on it and spit it out.

Some babies do not crawl but bottom shuffle. This looks sweet and may run in families. Most babies who do this miss out crawling and just go on to walking.

What she thinks: If you fancy yourself as a psychologist you can experiment on your baby by trying the three brick test. This is where you confuse your baby by sitting her down and handing her two bricks so that she holds one in each hand. If you hold out another brick to her (aim for the middle) she may stare at it with bewilderment, (this does not measure intelligence, okay?) look from hand to hand, look at the new brick and then back to the bricks she holds but not try to take the third brick. Or she may drop one brick and take the third. Or she may try to cradle all three bricks between chest and hands. Whatever she does she is a clever little thing because she is doing some adaptive development. The ability to reach out and take a brick is instinctive but here your baby at the tender age of nine months is beginning an intellectual process of working out what to do with that stupid third brick.

She also understands what psychologists call object permanence and looks for toys that she drops from her high chair rather than assuming they disappear forever. Although she understands no, she enjoys the ambiguity - she may keep going back to the banned activity and watch you out of corner of her eye to see what you think. It's hard to get on your discipline high horse at this age - easier to have a bit of a laugh with her.

How she behaves: She will hate to be separated from you and be unsettled once you are out of the room (this is different for babies who are already used to other caregivers - it does not mean your baby is screaming her lungs out at nursery). Bless her heart, she has a specific emotional attachment to her mum, and will treat you by sticking her fingers into your mouth as a sign of affection and pressing her face against yours. She may look anxious if you look different (so best not to dress up for that ABBA party in front of her). She will be most put out at being approached by a stranger.

How she speaks: She might manage an animal noise if you have roared to her consistently enough. She understands more than even an overachieving parent might expect and certainly more than she can speak. The sight of a bib means food to her, bye bye means you are leaving her and she will pucker up ready to cry. If you say Daddy is home, or where's Teddy, she will understand. She will chatter away with lots of consonants in an imitation of your speech. Research shows that she will prefer to listen to nursery rhymes than a nondescript musical tone. She can also understand "no", although obedience is something else.

What she can see: Her sight is gradually approaching that of an adult's. She can now focus on small objects.

What she can hear: She can now accurately locate sound. At seven months ringing a bell above her head would make her confused. Now she can he lift up her head to locate the sound

What she has in her mouth: From eight months onwards she will produce two more incisors at both the bottom and top.

What she likes to play: She likes pat-a-cake and familiar games and rhymes. She will enjoy lift the flap books and pictures of real life things like other babies and dogs and cats. (See top toys and top books for babies under one.) She will enjoy trying to stack things and put things into containers though this does not mean she will end up doing shelf work in Tesco's. She will enjoy cuddling a teddy or doll and undressing it. Hide and seek is also a favourite and continues to be one for many years.

It's helpful for you to do a running commentary on what you are doing with her even if it makes you feel like an idiot. If she lifts up her arms to be picked up, ask her "You want to be picked up?" The question is obviously rhetorical.

A word on reading our development calendar

It will save a lot of heartache if you bear in mind that milestones of development are not carved in granite, but widely variable. (See our behaviour/development discussion forum.) It is not uncommon to have isolated pockets of late development, such as late walkers and talkers, and much of the individual differences between the development of babies and children is genetically programmed - so try and resist the temptation to be a competitive parent. And bear in mind that some babies will be slower to develop in certain areas because they were born prematurely or because they are twins (or triplets). For more information on twins, triplets et al, see our multiple births discussion forum.

A minority of babies and children do have delays in development that may need specialist help. Doctors' textbooks tell them to take a parent's concerns about their child seriously. No health professional should ever trivialise a worry that you have about your child. If you are at all concerned, take her to see your GP.

We are also obviously aware that some children have special needs and the information in our developmental emails may not be relevant to them. We have included some site recommendations that may be useful in our web guide but the list is by no means exhaustive and we would really welcome other suggestions. If you have come across an organisation that you have found helpful, please email their web address to our webguide manager here. You can also seek advice from other parents via our Special Needs talk forum.